PageSpeed Insights

Values are estimated and may vary. The performance score is calculated directly from these metrics.See calculator.

0–49 50–89 90–100

First Contentful Paint

5.6 s

First Contentful Paint marks the time at which the first text or image is painted. Learn more about the First Contentful Paint metric.

Largest Contentful Paint

11.5 s

Largest Contentful Paint marks the time at which the largest text or image is painted. Learn more about the Largest Contentful Paint metric

Total Blocking Time

250 ms

Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more about the Total Blocking Time metric.

Cumulative Layout Shift

Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more about the Cumulative Layout Shift metric.

Speed Index

6.4 s

Speed Index shows how quickly the contents of a page are visibly populated. Learn more about the Speed Index metric.

Captured at Mar 10, 2025, 6:00 PM UTC
Emulated Moto G Power with Lighthouse 12.4.0
Unthrottled CPU/Memory Power: 379 CPU throttling: 1.2x slowdown (Simulated) Screen emulation: 412x823, DPR 1.75 Axe version: 4.10.2
Single page session
This data is taken from a single page session, as opposed to field data summarizing many sessions.
Initial page load
Slow 4G throttling
Network throttling: 150 ms TCP RTT, 1,638.4 kb/s throughput (Simulated) Browser location: North America
Using HeadlessChromium 133.0.6943.141 with lr
User agent (network): "Mozilla/5.0 (Linux; Android 11; moto g power (2022)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Mobile Safari/537.36"

Largest Contentful Paint element 11,480 ms

This is the largest contentful element painted within the viewport. Learn more about the Largest Contentful Paint elementLCP

Element
Got Nectar? Shop lower prices. <img src="https://media.4rgos.it/i/Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp" alt="Got Nectar? Shop lower prices." data-test="component-image" loading="auto">

Phase	% of LCP	Timing
TTFB	5%	600 ms
Load Delay	23%	2,580 ms
Load Time	5%	620 ms
Render Delay	67%	7,670 ms

Reduce unused JavaScript Potential savings of 522 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.LCPFCP

Use Webpack Bundle Analyzer to detect unused JavaScript code. Learn more

If you are not server-side rendering, split your JavaScript bundles with React.lazy(). Otherwise, code-split using a third-party library such as loadable-components.

URL	Transfer Size	Potential Savings
sainsburys.co.uk 1st party	517.4 KiB	288.1 KiB
/assets/app-174….js (www.sainsburys.co.uk)	402.7 KiB	231.8 KiB
/assets/120fac23-174….js (www.sainsburys.co.uk)	114.7 KiB	56.3 KiB
Google Tag Manager tag-manager	289.4 KiB	132.7 KiB
/gtag/js?id=… (www.googletagmanager.com)	136.0 KiB	54.6 KiB
/gtag/js?id=… (www.googletagmanager.com)	94.2 KiB	43.0 KiB
/gtag/js (www.googletagmanager.com)	59.2 KiB	35.1 KiB
Optanon consent-provider	112.4 KiB	61.0 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	112.4 KiB	61.0 KiB
Tealium tag-manager	84.2 KiB	40.6 KiB
…prod/utag.js (tags.tiqcdn.com)	84.2 KiB	40.6 KiB

Eliminate render-blocking resources Potential savings of 300 ms

Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles. Learn how to eliminate render-blocking resources.LCPFCP

Use the Gatsby Script API to defer loading of non-critical third-party scripts. Learn more.

URL	Transfer Size	Potential Savings
Tealium tag-manager	1.1 KiB	750 ms
…prod/utag.sync.js (tags.tiqcdn.com)	1.1 KiB	750 ms

Defer offscreen images Potential savings of 487 KiB

Consider lazy-loading offscreen and hidden images after all critical resources have finished loading to lower time to interactive. Learn how to defer offscreen images.LCPFCP

Use the gatsby-plugin-image component instead of <img> to automatically lazy-load images. Learn more.

	URL	Resource Size	Potential Savings
4rgos.it		442.1 KiB	442.1 KiB
platter of sandwiches <img src="https://media.4rgos.it/i/Argos/Sandwich%20GOL?w=600&poi={$this.metadata.po…" alt="platter of sandwiches " data-test="c004-image-logo-main-image" loading="auto">	…Argos/Sandwich%20GOL?w=… (media.4rgos.it)	47.6 KiB	47.6 KiB
Shop In-Season. <img src="https://media.4rgos.it/i/Argos/v2_C004_Shop_In_Season?w=600&poi={$this.met…" alt="Shop In-Season." data-test="c004-image-logo-main-image" loading="auto">	…Argos/v2_C004_S…?w=… (media.4rgos.it)	44.3 KiB	44.3 KiB
Feed your family for a fiver. <img src="https://media.4rgos.it/i/Argos/C004_feed_your_family?w=600&poi={$this.meta…" alt="Feed your family for a fiver." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_feed…?w=… (media.4rgos.it)	37.9 KiB	37.9 KiB
Meat Free Monday. <img src="https://media.4rgos.it/i/Argos/C004_meat_free_monday?w=600&poi={$this.meta…" alt="Meat Free Monday." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_meat…?w=… (media.4rgos.it)	35.7 KiB	35.7 KiB
New arrivals at habitat. <img src="https://media.4rgos.it/i/Argos/0724-600-300-habitat-3265660?w=600&poi={$th…" alt="New arrivals at habitat." data-test="c004-image-logo-main-image" loading="auto">	…Argos/0724-600-…?w=… (media.4rgos.it)	33.5 KiB	33.5 KiB
Budget Friendly. <img src="https://media.4rgos.it/i/Argos/C004_budget_friendly?w=600&poi={$this.metad…" alt="Budget Friendly." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_budg…?w=… (media.4rgos.it)	33.1 KiB	33.1 KiB
Taste the Difference. <img src="https://media.4rgos.it/i/Argos/v2_C004_TTD_Hub?w=600&poi={$this.metadata.p…" alt="Taste the Difference." data-test="c004-image-logo-main-image" loading="auto">	…Argos/v2_C004_TTD_Hub?w=… (media.4rgos.it)	27.1 KiB	27.1 KiB
Women in striped pink pyjama set <img src="https://media.4rgos.it/i/Argos/image_New_TU_24?w=600&poi={$this.metadata.p…" alt="Women in striped pink pyjama set" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image_New_TU_24?w=… (media.4rgos.it)	19.8 KiB	19.8 KiB
Shop Habitat 60th celebration. <img src="https://media.4rgos.it/i/Argos/Habitat_meganav?w=600&poi={$this.metadata.p…" alt="Shop Habitat 60th celebration." data-test="c004-image-logo-main-image" loading="auto">	…Argos/Habitat_meganav?w=… (media.4rgos.it)	19.6 KiB	19.6 KiB
Shop spring homeware edit. <img src="https://media.4rgos.it/i/Argos/0724-600-300-habitat-candle?w=600&poi={$thi…" alt="Shop spring homeware edit." data-test="c004-image-logo-main-image" loading="auto">	…Argos/0724-600-…?w=… (media.4rgos.it)	16.8 KiB	16.8 KiB
Woman on sofa hugging her daughter. <img src="https://media.4rgos.it/i/Argos/JS_Landing_Page_Dropdown_600x300px%20(002)?…" alt="Woman on sofa hugging her daughter." data-test="c004-image-logo-main-image" loading="auto">	…Argos/JS_Landin…%20(002)?w=… (media.4rgos.it)	15.8 KiB	15.8 KiB
100% renewable electricity* <img src="https://media.4rgos.it/i/Argos/couk_dropdown_energy?w=600&poi={$this.metad…" alt="100% renewable electricity*" data-test="c004-image-logo-main-image" loading="auto">	…Argos/couk_drop…?w=… (media.4rgos.it)	14.2 KiB	14.2 KiB
Sainsbury's Bank Travel Money. <img src="https://media.4rgos.it/i/Argos/MAR002711-021%20JS%20drop%20down%20225%20x%…" alt="Sainsbury's Bank Travel Money." data-test="c004-image-logo-main-image" loading="auto">	…Argos/MAR002711-021%20JS%20drop%20down%20225%20x%20124px?w=… (media.4rgos.it)	13.6 KiB	13.6 KiB
Cake on cake stand <img src="https://media.4rgos.it/i/Argos/Cake%20GOL?w=600&poi={$this.metadata.pointO…" alt="Cake on cake stand" data-test="c004-image-logo-main-image" loading="auto">	…Argos/Cake%20GOL?w=… (media.4rgos.it)	12.9 KiB	12.9 KiB
Girl in white fleece pyjama set <img src="https://media.4rgos.it/i/Argos/image2_New_TU_24?w=600&poi={$this.metadata.…" alt="Girl in white fleece pyjama set" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image2_New_TU_24?w=… (media.4rgos.it)	12.9 KiB	12.9 KiB
construction toy <img src="https://media.4rgos.it/i/Argos/sb-1422-225x150-argos-toyoffers?w=600&poi={…" alt="construction toy" data-test="c004-image-logo-main-image" loading="auto">	…Argos/sb-1422-2…?w=… (media.4rgos.it)	11.8 KiB	11.8 KiB
Man in green pyjama set <img src="https://media.4rgos.it/i/Argos/image1_New_TU_24?w=600&poi={$this.metadata.…" alt="Man in green pyjama set" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image1_New_TU_24?w=… (media.4rgos.it)	10.7 KiB	10.7 KiB
Man in green hoodie hugging a dog. <img src="https://media.4rgos.it/i/Argos/SB6935_MAR002981-007_Q4_2024_Pet_JS_Dropdow…" alt="Man in green hoodie hugging a dog." data-test="c004-image-logo-main-image" loading="auto">	…Argos/SB6935_MA…?w=… (media.4rgos.it)	9.8 KiB	9.8 KiB
Woman in pyjama set with stay cosy slogan <img src="https://media.4rgos.it/i/Argos/image3_New_TU_24?w=600&poi={$this.metadata.…" alt="Woman in pyjama set with stay cosy slogan" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image3_New_TU_24?w=… (media.4rgos.it)	6.9 KiB	6.9 KiB
Discover Nectar Prices. <img src="https://media.4rgos.it/i/Argos/v2_Discover_nectar_C004?w=600&poi={$this.me…" alt="Discover Nectar Prices." data-test="c004-image-logo-main-image" loading="auto">	…Argos/v2_Discov…?w=… (media.4rgos.it)	6.9 KiB	6.9 KiB
New In. <img src="https://media.4rgos.it/i/Argos/2123-225x150-ddn-argos-newin-3100567-303348…" alt="New In." data-test="c004-image-logo-main-image" loading="auto">	…Argos/2123-225x…?w=… (media.4rgos.it)	6.4 KiB	6.4 KiB
Clearance <img src="https://media.4rgos.it/i/Argos/sb-1422-225x150-argos-clearance?w=600&poi={…" alt="Clearance" data-test="c004-image-logo-main-image" loading="auto">	…Argos/sb-1422-2…?w=… (media.4rgos.it)	4.9 KiB	4.9 KiB
Optanon consent-provider		27.8 KiB	27.8 KiB
Company Logo <img alt="Company Logo" src="https://cdn-ukwest.onetrust.com/logos/e1fd2f29-c8cd-4679-82e1-451d39f5ae8a…">	…53f3532a-319c-45d4-b6eb-3922b10c275d/sainsburys.png (cdn-ukwest.onetrust.com)	25.0 KiB	25.0 KiB
Powered by Onetrust <img alt="Powered by Onetrust" src="https://cdn-ukwest.onetrust.com/logos/static/powered_by_logo.svg">	…static/powered_by_logo.svg (cdn-ukwest.onetrust.com)	2.8 KiB	2.8 KiB
Unattributable		16.7 KiB	16.7 KiB
Get it on Google Play <img src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9z…" alt="Get it on Google Play" width="135" height="40" data-testid="sainsburys-google-play-logo" class="Appsstyles__AppsImage-sc-15fzq3m-6 bxlJZa">	data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vc…	9.5 KiB	9.5 KiB
Download on the app store <img src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9z…" alt="Download on the app store" width="119" height="40" data-testid="sainsburys-app-store-logo" class="Appsstyles__AppsImage-sc-15fzq3m-6 bxlJZa">	data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vc…	7.2 KiB	7.2 KiB

Image elements do not have explicit width and height

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensionsCLS

	URL
4rgos.it
Book your click and collect. <img src="https://media.4rgos.it/i/Argos/C004_click_and_collect?w=600&poi={$this.met…" alt="Book your click and collect." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_clic…?w=… (media.4rgos.it)
Book a delivery. <img src="https://media.4rgos.it/i/Argos/COO4_Delivery?w=600&poi={$this.metadata.poi…" alt="Book a delivery." data-test="c004-image-logo-main-image" loading="auto">	…Argos/COO4_Delivery?w=… (media.4rgos.it)
Sainsbury's Chop Chop app. <img src="https://media.4rgos.it/i/Argos/COO4_Chop_Chop?w=600&poi={$this.metadata.po…" alt="Sainsbury's Chop Chop app." data-test="c004-image-logo-main-image" loading="auto">	…Argos/COO4_Chop_Chop?w=… (media.4rgos.it)
Sainsbury's Delivery Pass. <img src="https://media.4rgos.it/i/Argos/W1_C004_Delivery_Pass?w=600&poi={$this.meta…" alt="Sainsbury's Delivery Pass." data-test="c004-image-logo-main-image" loading="auto">	…Argos/W1_C004_D…?w=… (media.4rgos.it)

Serve images in next-gen formats Potential savings of 50 KiB

Image formats like WebP and AVIF often provide better compression than PNG or JPEG, which means faster downloads and less data consumption. Learn more about modern image formats.LCPFCP

Use the gatsby-plugin-image component instead of <img> to automatically optimize image format. Learn more.

URL	Resource Size	Potential Savings
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAe4AAAD6CAYAAABnJ…	34.4 KiB	25.3 KiB
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAfMAAAGmCAYAAABoT…	22.9 KiB	14.7 KiB
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAfIAAADiCAYAAAC1M…	14.8 KiB	9.8 KiB

Serve static assets with an efficient cache policy 56 resources found

A long cache lifetime can speed up repeat visits to your page. Learn more about efficient cache policies.

Configure caching for immutable assets. Learn more.

URL	Cache TTL	Transfer Size
4rgos.it		1,227 KiB
…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	65 KiB
…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	53 KiB
…Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	53 KiB
…Argos/M050_Larg…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	50 KiB
…Argos/M050_East…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	49 KiB
…Argos/M050_Half…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	49 KiB
…Argos/Sandwich%20GOL?w=… (media.4rgos.it)	30m	48 KiB
…Argos/v2_GoodTo…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	46 KiB
…Argos/v2_C004_S…?w=… (media.4rgos.it)	30m	45 KiB
…Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	40 KiB
…Argos/C004_feed…?w=… (media.4rgos.it)	30m	38 KiB
…Argos/COO4_Delivery?w=… (media.4rgos.it)	30m	37 KiB
…Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	36 KiB
…Argos/C004_meat…?w=… (media.4rgos.it)	30m	36 KiB
…Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	36 KiB
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	36 KiB
…Argos/0724-600-…?w=… (media.4rgos.it)	30m	34 KiB
…Argos/C004_budg…?w=… (media.4rgos.it)	30m	34 KiB
…Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	33 KiB
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	30 KiB
…Argos/v2_C004_TTD_Hub?w=… (media.4rgos.it)	30m	28 KiB
…Argos/0125-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	28 KiB
…Argos/4825-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	23 KiB
…Argos/image_New_TU_24?w=… (media.4rgos.it)	30m	20 KiB
…Argos/Habitat_meganav?w=… (media.4rgos.it)	30m	20 KiB
…Argos/nectarsig…%20(1)?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	20 KiB
…Argos/M050_couk…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	18 KiB
…Argos/ynp_js_n_…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	18 KiB
…Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	18 KiB
…Argos/0724-600-…?w=… (media.4rgos.it)	30m	17 KiB
…Argos/JS_Landin…%20(002)?w=… (media.4rgos.it)	30m	16 KiB
…Argos/W1_C004_D…?w=… (media.4rgos.it)	30m	15 KiB
…Argos/couk_drop…?w=… (media.4rgos.it)	30m	15 KiB
…Argos/MAR002711-021%20JS%20drop%20down%20225%20x%20124px?w=… (media.4rgos.it)	30m	14 KiB
…Argos/C004_clic…?w=… (media.4rgos.it)	30m	14 KiB
…Argos/Cake%20GOL?w=… (media.4rgos.it)	30m	13 KiB
…Argos/image2_New_TU_24?w=… (media.4rgos.it)	30m	13 KiB
…Argos/sb-1422-2…?w=… (media.4rgos.it)	30m	12 KiB
…Argos/image1_New_TU_24?w=… (media.4rgos.it)	30m	11 KiB
…Argos/SB6935_MA…?w=… (media.4rgos.it)	30m	10 KiB
…Argos/COO4_Chop_Chop?w=… (media.4rgos.it)	30m	10 KiB
…Argos/image3_New_TU_24?w=… (media.4rgos.it)	30m	7 KiB
…Argos/v2_Discov…?w=… (media.4rgos.it)	30m	7 KiB
…Argos/2123-225x…?w=… (media.4rgos.it)	30m	7 KiB
…Argos/sb-1422-2…?w=… (media.4rgos.it)	30m	5 KiB
Optanon consent-provider		150 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	1d	113 KiB
…53f3532a-319c-45d4-b6eb-3922b10c275d/sainsburys.png (cdn-ukwest.onetrust.com)	1d	26 KiB
/scripttemplates/otSDKStub.js (cdn-ukwest.onetrust.com)	1d	8 KiB
…static/powered_by_logo.svg (cdn-ukwest.onetrust.com)	1d	3 KiB
Tealium tag-manager		103 KiB
…prod/utag.js (tags.tiqcdn.com)	5m	85 KiB
…prod/utag.351.js?utv=ut4.44.202… (tags.tiqcdn.com)	5m	10 KiB
…prod/utag.282.js?utv=ut4.44.202… (tags.tiqcdn.com)	5m	3 KiB
…prod/utag.289.js?utv=ut4.44.202… (tags.tiqcdn.com)	5m	3 KiB
…prod/utag.sync.js (tags.tiqcdn.com)	5m	1 KiB
…tiqapp/utag.v.js?a=sainsburys/groceries/202…&cb=174… (tags.tiqcdn.com)	5m	1 KiB
New Relic utility		1 KiB
/1/d471046ff6?a=… (bam.nr-data.net)	None	1 KiB

Properly size images Potential savings of 418 KiB

Serve images that are appropriately-sized to save cellular data and improve load time. Learn how to size images.LCPFCP

Use the gatsby-plugin-image component to set appropriate sizes. Learn more.

	URL	Resource Size	Potential Savings
4rgos.it		672.4 KiB	418.2 KiB
Explore Habitat homeware. <img src="https://media.4rgos.it/i/Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp" alt="Explore Habitat homeware." data-test="component-image" loading="auto">	…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	64.2 KiB	47.4 KiB
Best of British. <img src="https://media.4rgos.it/i/Argos/v2_GoodTokKow_BestOfBrtish_n_couk_topright_…" alt="Best of British." data-test="component-image" loading="auto">	…Argos/v2_GoodTo…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	45.3 KiB	30.7 KiB
Home energy that feels rewarding. <img src="https://media.4rgos.it/i/Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp" alt="Home energy that feels rewarding." data-test="component-image" loading="auto">	…Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	40.0 KiB	29.0 KiB
Mother's Day. <img src="https://media.4rgos.it/i/Argos/W1_M050_couk_Mothers_day?maxW=1200&qlt=75&f…" alt="Mother's Day." data-test="component-image" loading="auto">	…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	52.4 KiB	27.3 KiB
Shop In Season. <img src="https://media.4rgos.it/i/Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp" alt="Shop In Season." data-test="component-image" loading="auto">	…Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	52.2 KiB	27.2 KiB
Large egg stunt from £2.50. <img src="https://media.4rgos.it/i/Argos/M050_Large_eggs_stunt_Couk?maxW=1200&qlt=75…" alt="Large egg stunt from £2.50." data-test="component-image" loading="auto">	…Argos/M050_Larg…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	49.0 KiB	25.5 KiB
How we’re working towards our plan for better. <img src="https://media.4rgos.it/i/Argos/M050_co_uk_plan_for_better?maxW=1200&qlt=75…" alt="How we’re working towards our plan for better." data-test="component-image" loading="auto">	…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	35.2 KiB	25.5 KiB
Easter is coming. <img src="https://media.4rgos.it/i/Argos/M050_Easter_Event_Co-uk?maxW=1200&qlt=75&fm…" alt="Easter is coming." data-test="component-image" loading="auto">	…Argos/M050_East…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	48.4 KiB	25.2 KiB
Half Price Freezer Fillers. <img src="https://media.4rgos.it/i/Argos/M050_Half_price_freezer_Co-Uk_?maxW=1200&ql…" alt="Half Price Freezer Fillers." data-test="component-image" loading="auto">	…Argos/M050_Half…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	48.3 KiB	25.2 KiB
Sainsbury’s Bank Pet Insurance. <img src="https://media.4rgos.it/i/Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp" alt="Sainsbury’s Bank Pet Insurance." data-test="component-image" loading="auto">	…Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	35.4 KiB	23.9 KiB
Donate to Comic Relief. <img src="https://media.4rgos.it/i/Argos/M050_co_uk_Comic_Relief?maxW=1200&qlt=75&fm…" alt="Donate to Comic Relief." data-test="component-image" loading="auto">	…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	29.4 KiB	21.3 KiB
New season. <img src="https://media.4rgos.it/i/Argos/0125-m050-tu-work-everytime?maxW=1200&qlt=7…" alt="New season." data-test="component-image" loading="auto">	…Argos/0125-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	27.0 KiB	20.0 KiB
Ramadan. <img src="https://media.4rgos.it/i/Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp" alt="Ramadan." data-test="component-image" loading="auto">	…Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	35.9 KiB	18.7 KiB
Buy 3 or more bottles save 25%. <img src="https://media.4rgos.it/i/Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp" alt="Buy 3 or more bottles save 25%." data-test="component-image" loading="auto">	…Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	32.5 KiB	16.9 KiB
Thanks Mum. <img src="https://media.4rgos.it/i/Argos/4825-m050-mothers-day?maxW=1200&qlt=75&fmt=…" alt="Thanks Mum." data-test="component-image" loading="auto">	…Argos/4825-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	22.4 KiB	15.5 KiB
Start saving more, now. <img src="https://media.4rgos.it/i/Argos/nectarsignup_js_n_nv_pl_couk_pod_1_n%20(1)?…" alt="Start saving more, now." data-test="component-image" loading="auto">	…Argos/nectarsig…%20(1)?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	19.4 KiB	13.3 KiB
Prices matched. <img src="https://media.4rgos.it/i/Argos/M050_couk_Aldi_price_match?maxW=1200&qlt=75…" alt="Prices matched." data-test="component-image" loading="auto">	…Argos/M050_couk…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	17.9 KiB	12.9 KiB
Exclusive prices on items we think you’ll love. <img src="https://media.4rgos.it/i/Argos/ynp_js_n_yournectarprices_pl_couk_banner_n_…" alt="Exclusive prices on items we think you’ll love." data-test="component-image" loading="auto">	…Argos/ynp_js_n_…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	17.4 KiB	12.6 KiB

Avoid serving legacy JavaScript to modern browsers Potential savings of 13 KiB

Polyfills and transforms enable legacy browsers to use new JavaScript features. However, many aren't necessary for modern browsers. For your bundled JavaScript, adopt a modern script deployment strategy using module/nomodule feature detection to reduce the amount of code shipped to modern browsers, while retaining support for legacy browsers. Learn how to serve modern JavaScriptLCPFCP

URL		Potential Savings
Optanon consent-provider		7.2 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)		7.2 KiB
…202501.1.0/otBannerSdk.js:7:7428 (cdn-ukwest.onetrust.com)	Array.prototype.fill
Tealium tag-manager		5.8 KiB
…prod/utag.js (tags.tiqcdn.com)		5.8 KiB
…prod/utag.js:363:268 (tags.tiqcdn.com)	Date.now
sainsburys.co.uk 1st party		0.1 KiB
/assets/app-174….js (www.sainsburys.co.uk)		0.1 KiB
/assets/app-174….js:14:5482 (www.sainsburys.co.uk)	@babel/plugin-transform-classes

Reduce unused CSS Potential savings of 97 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.LCPFCP

Use the PurgeCSS Gatsby plugin to remove unused rules from stylesheets. Learn more.

URL	Transfer Size	Potential Savings
:export{color_primary:#375ea9;color_primary_light:#e7eff7;color_primary_dark:#08305f;color_secondar…	84.2 KiB	78.8 KiB
#onetrust-banner-sdk .onetrust-vendors-list-handler{cursor:pointer;color:#1f96db;font-size:inherit; … } …	20.6 KiB	18.0 KiB

URL

Transfer Size

Potential Savings

:export{color_primary:#375ea9;color_primary_light:#e7eff7;color_primary_dark:#08305f;color_secondar…

84.2 KiB

78.8 KiB

#onetrust-banner-sdk .onetrust-vendors-list-handler{cursor:pointer;color:#1f96db;font-size:inherit; … } …

20.6 KiB

18.0 KiB

Avoid enormous network payloads Total size was 2,669 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

URL	Transfer Size
sainsburys.co.uk 1st party	687.6 KiB
/assets/app-174….js (www.sainsburys.co.uk)	403.9 KiB
https://www.sainsburys.co.uk	167.8 KiB
/assets/120fac23-174….js (www.sainsburys.co.uk)	115.9 KiB
Google Tag Manager tag-manager	292.5 KiB
/gtag/js?id=… (www.googletagmanager.com)	137.0 KiB
/gtag/js?id=… (www.googletagmanager.com)	95.3 KiB
/gtag/js (www.googletagmanager.com)	60.3 KiB
4rgos.it	117.5 KiB
…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	64.7 KiB
…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	52.8 KiB
Optanon consent-provider	113.4 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	113.4 KiB
Tealium tag-manager	84.8 KiB
…prod/utag.js (tags.tiqcdn.com)	84.8 KiB

Avoid an excessive DOM size 1,062 elements

A large DOM will increase memory usage, cause longer style calculations, and produce costly layout reflows. Learn how to avoid an excessive DOM size.TBT

Consider using a "windowing" library like react-window to minimize the number of DOM nodes created if you are rendering many repeated elements on the page. Learn more. Also, minimize unnecessary re-renders using shouldComponentUpdate, PureComponent, or React.memo and skip effects only until certain dependencies have changed if you are using the Effect hook to improve runtime performance.

Statistic	Element	Value
Total DOM Elements		1,062
Maximum DOM Depth	div.Rowstyles__GridRow-sc-1w6itvg-0 > div.ImageCtaCardstyles__StyledImageContainer-sc-1jyhigy-1 > picture > source <source type="image/webp" srcset="//media.4rgos.it/i/Argos/v2_Discover_nectar_C004?w=600&poi={$this.metadata…">	19
Maximum Child Elements	body <body>	14

Avoid long main-thread tasks 9 long tasks found

Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay. Learn how to avoid long main-thread tasksTBT

URL	Start Time	Duration
sainsburys.co.uk 1st party		552 ms
/assets/120fac23-174….js (www.sainsburys.co.uk)	13,843 ms	167 ms
/assets/120fac23-174….js (www.sainsburys.co.uk)	14,010 ms	157 ms
/assets/framework-174….js (www.sainsburys.co.uk)	14,167 ms	96 ms
/assets/framework-174….js (www.sainsburys.co.uk)	3,902 ms	77 ms
https://www.sainsburys.co.uk	1,696 ms	55 ms
Google Tag Manager tag-manager		183 ms
/gtag/js?id=… (www.googletagmanager.com)	9,933 ms	125 ms
/gtag/js?id=… (www.googletagmanager.com)	7,383 ms	58 ms
Unattributable		118 ms
Unattributable	12,499 ms	118 ms
Tealium tag-manager		73 ms
…prod/utag.js (tags.tiqcdn.com)	3,979 ms	73 ms

Minimize third-party usage Third-party code blocked the main thread for 110 ms

Third-party code can significantly impact load performance. Limit the number of redundant third-party providers and try to load third-party code after your page has primarily finished loading. Learn how to minimize third-party impact.TBT

Third-Party	Transfer Size	Main-Thread Blocking Time
Google Tag Manager tag-manager	293 KiB	83 ms
/gtag/js?id=… (www.googletagmanager.com)	137 KiB	75 ms
/gtag/js?id=… (www.googletagmanager.com)	95 KiB	8 ms
/gtag/js (www.googletagmanager.com)	60 KiB	0 ms
Tealium tag-manager	103 KiB	22 ms
…prod/utag.js (tags.tiqcdn.com)	85 KiB	22 ms
…prod/utag.351.js?utv=ut4.44.202… (tags.tiqcdn.com)	10 KiB	0 ms
…prod/utag.282.js?utv=ut4.44.202… (tags.tiqcdn.com)	3 KiB	0 ms
…prod/utag.289.js?utv=ut4.44.202… (tags.tiqcdn.com)	3 KiB	0 ms
…prod/utag.sync.js (tags.tiqcdn.com)	1 KiB	0 ms
…tiqapp/utag.v.js?a=sainsburys/groceries/202…&cb=174… (tags.tiqcdn.com)	1 KiB	0 ms
4rgos.it	1,227 KiB	0 ms
…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	65 KiB	0 ms
…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	53 KiB	0 ms
…Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	53 KiB	0 ms
…Argos/M050_Larg…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	50 KiB	0 ms
…Argos/M050_East…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	49 KiB	0 ms
…Argos/M050_Half…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	49 KiB	0 ms
…Argos/Sandwich%20GOL?w=… (media.4rgos.it)	48 KiB	0 ms
…Argos/v2_GoodTo…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	46 KiB	0 ms
…Argos/v2_C004_S…?w=… (media.4rgos.it)	45 KiB	0 ms
…Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	40 KiB	0 ms
…Argos/C004_feed…?w=… (media.4rgos.it)	38 KiB	0 ms
…Argos/COO4_Delivery?w=… (media.4rgos.it)	37 KiB	0 ms
…Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	36 KiB	0 ms
…Argos/C004_meat…?w=… (media.4rgos.it)	36 KiB	0 ms
…Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	36 KiB	0 ms
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	36 KiB	0 ms
…Argos/0724-600-…?w=… (media.4rgos.it)	34 KiB	0 ms
…Argos/C004_budg…?w=… (media.4rgos.it)	34 KiB	0 ms
…Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	33 KiB	0 ms
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30 KiB	0 ms
…Argos/v2_C004_TTD_Hub?w=… (media.4rgos.it)	28 KiB	0 ms
…Argos/0125-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	28 KiB	0 ms
…Argos/4825-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	23 KiB	0 ms
…Argos/image_New_TU_24?w=… (media.4rgos.it)	20 KiB	0 ms
…Argos/Habitat_meganav?w=… (media.4rgos.it)	20 KiB	0 ms
…Argos/nectarsig…%20(1)?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	20 KiB	0 ms
…Argos/M050_couk…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	18 KiB	0 ms
…Argos/ynp_js_n_…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	18 KiB	0 ms
…Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	18 KiB	0 ms
…Argos/0724-600-…?w=… (media.4rgos.it)	17 KiB	0 ms
…Argos/JS_Landin…%20(002)?w=… (media.4rgos.it)	16 KiB	0 ms
…Argos/W1_C004_D…?w=… (media.4rgos.it)	15 KiB	0 ms
…Argos/couk_drop…?w=… (media.4rgos.it)	15 KiB	0 ms
…Argos/MAR002711-021%20JS%20drop%20down%20225%20x%20124px?w=… (media.4rgos.it)	14 KiB	0 ms
…Argos/C004_clic…?w=… (media.4rgos.it)	14 KiB	0 ms
…Argos/Cake%20GOL?w=… (media.4rgos.it)	13 KiB	0 ms
…Argos/image2_New_TU_24?w=… (media.4rgos.it)	13 KiB	0 ms
…Argos/sb-1422-2…?w=… (media.4rgos.it)	12 KiB	0 ms
…Argos/image1_New_TU_24?w=… (media.4rgos.it)	11 KiB	0 ms
…Argos/SB6935_MA…?w=… (media.4rgos.it)	10 KiB	0 ms
…Argos/COO4_Chop_Chop?w=… (media.4rgos.it)	10 KiB	0 ms
…Argos/image3_New_TU_24?w=… (media.4rgos.it)	7 KiB	0 ms
…Argos/v2_Discov…?w=… (media.4rgos.it)	7 KiB	0 ms
…Argos/2123-225x…?w=… (media.4rgos.it)	7 KiB	0 ms
…Argos/sb-1422-2…?w=… (media.4rgos.it)	5 KiB	0 ms
Optanon consent-provider	199 KiB	0 ms
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	113 KiB	0 ms
…53f3532a-319c-45d4-b6eb-3922b10c275d/sainsburys.png (cdn-ukwest.onetrust.com)	26 KiB	0 ms
…0193644a-194e-7364-a9db-7dc86b85eecd/en.json (cdn-ukwest.onetrust.com)	22 KiB	0 ms
…v2/otPcCenter.json (cdn-ukwest.onetrust.com)	13 KiB	0 ms
/scripttemplates/otSDKStub.js (cdn-ukwest.onetrust.com)	8 KiB	0 ms
…assets/otCommonStyles.css (cdn-ukwest.onetrust.com)	5 KiB	0 ms
…assets/otFlat.json (cdn-ukwest.onetrust.com)	4 KiB	0 ms
…static/powered_by_logo.svg (cdn-ukwest.onetrust.com)	3 KiB	0 ms
…53f3532a-319c-45d4-b6eb-3922b10c275d/53f3532a-319c-45d4-b….json (cdn-ukwest.onetrust.com)	2 KiB	0 ms
…static/ot_guard_logo.svg (cdn-ukwest.onetrust.com)	1 KiB	0 ms
…geo/location (geolocation.onetrust.com)	0 KiB	0 ms
New Relic utility	19 KiB	0 ms
/nr-spa-1216.min.js (js-agent.newrelic.com)	18 KiB	0 ms
/1/d471046ff6?a=… (bam.nr-data.net)	1 KiB	0 ms
…1/d471046ff6?a=… (bam.nr-data.net)	0 KiB	0 ms
Google Analytics analytics	1 KiB	0 ms
/g/collect?v=… (www.google-analytics.com)	1 KiB	0 ms
Google/Doubleclick Ads ad	1 KiB	0 ms
…activity/src=9427595;type=saigo;cat=cat_golp;ord=425…;npa=1;gd… (ade.googlesyndication.com)	1 KiB	0 ms
/ccm/collect?en=… (pagead2.googlesyndication.com)	0 KiB	0 ms

Avoid non-composited animations 1 animated element found

Animations which are not composited can be janky and increase CLS. Learn how to avoid non-composited animationsCLS

Element	Name
Cookie Settings <a id="ot-sdk-btn" class="FooterLegalsstyles__ListHorizontalLinks-sc-1pjsnrc-2 kSmSif ot-sdk-show-se…" href="#" data-action="footer" data-label="Cookie Settings" data-position="footer,5,4" data-testid="footer.legals.cookie.preference">
Unsupported CSS Property: color	color

Avoid chaining critical requests 3 chains found

The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load. Learn how to avoid chaining critical requests.

Maximum critical path latency: 621.619 ms

Initial Navigation

https://www.sainsburys.co.uk

…prod/utag.sync.js

(tags.tiqcdn.com)

- 17.24 ms, 1.11 KiB

…static/mary_ann-regular-c01a3f1….woff2

(www.sainsburys.co.uk)

- 151.595 ms, 27.70 KiB

…static/mary_ann-extrabold-39e9c61….woff2

(www.sainsburys.co.uk)

- 153.134 ms, 28.82 KiB

More information about the performance of your application. These numbers don't directly affect the Performance score.

Show Hide

Minify CSS

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.LCPFCP

If your build system minifies CSS files automatically, ensure that you are deploying the production build of your application. You can check this with the React Developer Tools extension. Learn more.

Minify JavaScript

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.LCPFCP

If your build system minifies JS files automatically, ensure that you are deploying the production build of your application. You can check this with the React Developer Tools extension. Learn more.

Efficiently encode images

Optimized images load faster and consume less cellular data. Learn how to efficiently encode images.LCPFCP

Use the gatsby-plugin-image component instead of <img> to adjust image quality. Learn more.

Enable text compression

Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes. Learn more about text compression.LCPFCP

Preconnect to required origins

Consider adding preconnect or dns-prefetch resource hints to establish early connections to important third-party origins. Learn how to preconnect to required origins.LCPFCP

Initial server response time was short Root document took 140 ms

Keep the server response time for the main document short because all other requests depend on it. Learn more about the Time to First Byte metric.LCPFCP

If you are server-side rendering any React components, consider using renderToPipeableStream() or renderToStaticNodeStream() to allow the client to receive and hydrate different parts of the markup instead of all at once. Learn more.

URL	Time Spent
sainsburys.co.uk 1st party	140 ms
https://www.sainsburys.co.uk	140 ms

Avoid multiple page redirects

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.LCPFCP

If you are using React Router, minimize usage of the <Redirect> component for route navigations.

Use video formats for animated content

Large GIFs are inefficient for delivering animated content. Consider using MPEG4/WebM videos for animations and PNG/WebP for static images instead of GIF to save network bytes. Learn more about efficient video formatsLCPFCP

Remove duplicate modules in JavaScript bundles

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity. LCPFCP

Preload Largest Contentful Paint image

If the LCP element is dynamically added to the page, you should preload the image in order to improve LCP. Learn more about preloading LCP elements.LCP

Use the gatsby-plugin-image component and set the loading prop to eager. Learn more.

User Timing marks and measures

Consider instrumenting your app with the User Timing API to measure your app's real-world performance during key user experiences. Learn more about User Timing marks.

Use the React DevTools Profiler, which makes use of the Profiler API, to measure the rendering performance of your components. Learn more.

JavaScript execution time 1.0 s

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.TBT

URL	Total CPU Time	Script Evaluation	Script Parse
sainsburys.co.uk 1st party	908 ms	608 ms	11 ms
/assets/120fac23-174….js (www.sainsburys.co.uk)	351 ms	324 ms	5 ms
/assets/framework-174….js (www.sainsburys.co.uk)	287 ms	220 ms	3 ms
https://www.sainsburys.co.uk	270 ms	64 ms	4 ms
Unattributable	305 ms	36 ms	0 ms
Unattributable	305 ms	36 ms	0 ms
Google Tag Manager tag-manager	208 ms	176 ms	12 ms
/gtag/js?id=… (www.googletagmanager.com)	149 ms	122 ms	7 ms
/gtag/js?id=… (www.googletagmanager.com)	59 ms	54 ms	5 ms
Tealium tag-manager	147 ms	77 ms	6 ms
…prod/utag.js (tags.tiqcdn.com)	147 ms	77 ms	6 ms
Optanon consent-provider	121 ms	84 ms	9 ms
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	121 ms	84 ms	9 ms

Minimizes main-thread work 1.8 s

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread workTBT

Category	Time Spent
Script Evaluation	1,058 ms
Style & Layout	220 ms
Other	193 ms
Garbage Collection	145 ms
Script Parsing & Compilation	91 ms
Parse HTML & CSS	79 ms
Rendering	37 ms

All text remains visible during webfont loads

Leverage the font-display CSS feature to ensure text is user-visible while webfonts are loading. Learn more about font-display.

Lazy load third-party resources with facades

Some third-party embeds can be lazy loaded. Consider replacing them with a facade until they are required. Learn how to defer third-parties with a facade.TBT

Largest Contentful Paint image was not lazily loaded

Above-the-fold images that are lazily loaded render later in the page lifecycle, which can delay the largest contentful paint. Learn more about optimal lazy loading.LCP

Element
Got Nectar? Shop lower prices. <img src="https://media.4rgos.it/i/Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp" alt="Got Nectar? Shop lower prices." data-test="component-image" loading="auto">

Avoid large layout shifts

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLSCLS

Uses passive listeners to improve scrolling performance

Consider marking your touch and wheel event listeners as passive to improve your page's scroll performance. Learn more about adopting passive event listeners.

Avoids document.write()

For users on slow connections, external scripts dynamically injected via document.write() can delay page load by tens of seconds. Learn how to avoid document.write().

Has a <meta name="viewport"> tag with width or initial-scale

A <meta name="viewport"> not only optimizes your app for mobile screen sizes, but also prevents a 300 millisecond delay to user input. Learn more about using the viewport meta tag.

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Background and foreground colors do not have a sufficient contrast ratio.

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
Manage preferences <button id="onetrust-pc-btn-handler" class="cookie-setting-link">
Continue without accepting <button id="onetrust-reject-all-handler">
Accept all <button id="onetrust-accept-btn-handler">

These are opportunities to improve the legibility of your content.

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Interactive controls are keyboard focusable

Custom interactive controls are keyboard focusable and display a focus indicator. Learn how to make custom controls focusable.

Interactive elements indicate their purpose and state

Interactive elements, such as links and buttons, should indicate their state and be distinguishable from non-interactive elements. Learn how to decorate interactive elements with affordance hints.

The page has a logical tab order

Tabbing through the page follows the visual layout. Users cannot focus elements that are offscreen. Learn more about logical tab ordering.

Visual order on the page follows DOM order

DOM order matches the visual order, improving navigation for assistive technology. Learn more about DOM and visual ordering.

User focus is not accidentally trapped in a region

A user can tab into and out of any control or region without accidentally trapping their focus. Learn how to avoid focus traps.

The user's focus is directed to new content added to the page

If new content, such as a dialog, is added to the page, the user's focus is directed to it. Learn how to direct focus to new content.

HTML5 landmark elements are used to improve navigation

Landmark elements (<main>, <nav>, etc.) are used to improve the keyboard navigation of the page for assistive technology. Learn more about landmark elements.

Offscreen content is hidden from assistive technology

Offscreen content is hidden with display: none or aria-hidden=true. Learn how to properly hide offscreen content.

Custom controls have associated labels

Custom interactive controls have associated labels, provided by aria-label or aria-labelledby. Learn more about custom controls and labels.

Custom controls have ARIA roles

Custom interactive controls have appropriate ARIA roles. Learn how to add roles to custom controls.

These items address areas which an automated testing tool cannot cover. Learn more in our guide on conducting an accessibility review.

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[aria-*] attributes match their roles

Each ARIA role supports a specific subset of aria-* attributes. Mismatching these invalidates the aria-* attributes. Learn how to match ARIA attributes to their roles.

[aria-hidden="true"] is not present on the document <body>

Assistive technologies, like screen readers, work inconsistently when aria-hidden="true" is set on the document <body>. Learn how aria-hidden affects the document body.

[role]s have all required [aria-*] attributes

Some ARIA roles have required attributes that describe the state of the element to screen readers. Learn more about roles and required attributes.

[aria-*] attributes have valid values

Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more about valid values for ARIA attributes.

[aria-*] attributes are valid and not misspelled

Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid names. Learn more about valid ARIA attributes.

Buttons have an accessible name

When a button doesn't have an accessible name, screen readers announce it as "button", making it unusable for users who rely on screen readers. Learn how to make buttons more accessible.

Image elements have [alt] attributes

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the alt attribute.

[user-scalable="no"] is not used in the <meta name="viewport"> element and the [maximum-scale] attribute is not less than 5.

Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.

ARIA attributes are used as specified for the element's role

Some ARIA attributes are only allowed on an element under certain conditions. Learn more about conditional ARIA attributes.

Elements with role="dialog" or role="alertdialog" have accessible names.

ARIA dialog elements without accessible names may prevent screen readers users from discerning the purpose of these elements. Learn how to make ARIA dialog elements more accessible.

[aria-hidden="true"] elements do not contain focusable descendents

Focusable descendents within an [aria-hidden="true"] element prevent those interactive elements from being available to users of assistive technologies like screen readers. Learn how aria-hidden affects focusable elements.

Elements use only permitted ARIA attributes

Using ARIA attributes in roles where they are prohibited can mean that important information is not communicated to users of assistive technologies. Learn more about prohibited ARIA roles.

[role] values are valid

ARIA roles must have valid values in order to perform their intended accessibility functions. Learn more about valid ARIA roles.

Document has a <title> element

The title gives screen reader users an overview of the page, and search engine users rely on it heavily to determine if a page is relevant to their search. Learn more about document titles.

<html> element has a [lang] attribute

If a page doesn't specify a lang attribute, a screen reader assumes that the page is in the default language that the user chose when setting up the screen reader. If the page isn't actually in the default language, then the screen reader might not announce the page's text correctly. Learn more about the lang attribute.

<html> element has a valid value for its [lang] attribute

Specifying a valid BCP 47 language helps screen readers announce text properly. Learn how to use the lang attribute.

Form elements have associated labels

Labels ensure that form controls are announced properly by assistive technologies, like screen readers. Learn more about form element labels.

Links are distinguishable without relying on color.

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Links have a discernible name

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Lists contain only <li> elements and script supporting elements (<script> and <template>).

Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. Learn more about proper list structure.

List items (<li>) are contained within <ul>, <ol> or <menu> parent elements

Screen readers require list items (<li>) to be contained within a parent <ul>, <ol> or <menu> to be announced properly. Learn more about proper list structure.

Select elements have associated label elements.

Form elements without effective labels can create frustrating experiences for screen reader users. Learn more about the select element.

No element has a [tabindex] value greater than 0

A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. Learn more about the tabindex attribute.

Touch targets have sufficient size and spacing.

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Heading elements appear in a sequentially-descending order

Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. Learn more about heading order.

Uses ARIA roles only on compatible elements

Many HTML elements can only be assigned certain ARIA roles. Using ARIA roles where they are not allowed can interfere with the accessibility of the web page. Learn more about ARIA roles.

Deprecated ARIA roles were not used

Deprecated ARIA roles may not be processed correctly by assistive technology. Learn more about deprecated ARIA roles.

Image elements do not have [alt] attributes that are redundant text.

Informative elements should aim for short, descriptive alternative text. Alternative text that is exactly the same as the text adjacent to the link or image is potentially confusing for screen reader users, because the text will be read twice. Learn more about the alt attribute.

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[accesskey] values are unique

Access keys let users quickly focus a part of the page. For proper navigation, each access key must be unique. Learn more about access keys.

button, link, and menuitem elements have accessible names

When an element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to make command elements more accessible.

ARIA input fields have accessible names

When an input field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about input field labels.

ARIA meter elements have accessible names

When a meter element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to name meter elements.

ARIA progressbar elements have accessible names

When a progressbar element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to label progressbar elements.

Elements with an ARIA [role] that require children to contain a specific [role] have all required children.

Some ARIA parent roles must contain specific child roles to perform their intended accessibility functions. Learn more about roles and required children elements.

[role]s are contained by their required parent element

Some ARIA child roles must be contained by specific parent roles to properly perform their intended accessibility functions. Learn more about ARIA roles and required parent element.

Elements with the role=text attribute do not have focusable descendents.

Adding role=text around a text node split by markup enables VoiceOver to treat it as one phrase, but the element's focusable descendents will not be announced. Learn more about the role=text attribute.

ARIA toggle fields have accessible names

When a toggle field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about toggle fields.

ARIA treeitem elements have accessible names

When a treeitem element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about labeling treeitem elements.

The page contains a heading, skip link, or landmark region

Adding ways to bypass repetitive content lets keyboard users navigate the page more efficiently. Learn more about bypass blocks.

<dl>'s contain only properly-ordered <dt> and <dd> groups, <script>, <template> or <div> elements.

When definition lists are not properly marked up, screen readers may produce confusing or inaccurate output. Learn how to structure definition lists correctly.

Definition list items are wrapped in <dl> elements

Definition list items (<dt> and <dd>) must be wrapped in a parent <dl> element to ensure that screen readers can properly announce them. Learn how to structure definition lists correctly.

ARIA IDs are unique

The value of an ARIA ID must be unique to prevent other instances from being overlooked by assistive technologies. Learn how to fix duplicate ARIA IDs.

No form fields have multiple labels

Form fields with multiple labels can be confusingly announced by assistive technologies like screen readers which use either the first, the last, or all of the labels. Learn how to use form labels.

<frame> or <iframe> elements have a title

Screen reader users rely on frame titles to describe the contents of frames. Learn more about frame titles.

<html> element has an [xml:lang] attribute with the same base language as the [lang] attribute.

If the webpage does not specify a consistent language, then the screen reader might not announce the page's text correctly. Learn more about the lang attribute.

Input buttons have discernible text.

Adding discernable and accessible text to input buttons may help screen reader users understand the purpose of the input button. Learn more about input buttons.

<input type="image"> elements have [alt] text

When an image is being used as an <input> button, providing alternative text can help screen reader users understand the purpose of the button. Learn about input image alt text.

The document does not use <meta http-equiv="refresh">

Users do not expect a page to refresh automatically, and doing so will move focus back to the top of the page. This may create a frustrating or confusing experience. Learn more about the refresh meta tag.

<object> elements have alternate text

Screen readers cannot translate non-text content. Adding alternate text to <object> elements helps screen readers convey meaning to users. Learn more about alt text for object elements.

Tables have different content in the summary attribute and <caption>.

The summary attribute should describe the table structure, while <caption> should have the onscreen title. Accurate table mark-up helps users of screen readers. Learn more about summary and caption.

Cells in a <table> element that use the [headers] attribute refer to table cells within the same table.

Screen readers have features to make navigating tables easier. Ensuring <td> cells using the [headers] attribute only refer to other cells in the same table may improve the experience for screen reader users. Learn more about the headers attribute.

<th> elements and elements with [role="columnheader"/"rowheader"] have data cells they describe.

Screen readers have features to make navigating tables easier. Ensuring table headers always refer to some set of cells may improve the experience for screen reader users. Learn more about table headers.

[lang] attributes have a valid value

Specifying a valid BCP 47 language on elements helps ensure that text is pronounced correctly by a screen reader. Learn how to use the lang attribute.

<video> elements contain a <track> element with [kind="captions"]

When a video provides a caption it is easier for deaf and hearing impaired users to access its information. Learn more about video captions.

Best Practices

Uses deprecated APIs 1 warning found

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Deprecation / Warning	Source
sainsburys.co.uk 1st party
Unload event listeners are deprecated and will be removed.	https://www.sainsburys.co.uk:302:29511

Detected JavaScript libraries

All front-end JavaScript libraries detected on the page. Learn more about this JavaScript library detection diagnostic audit.

Name	Version
jQuery	3.5.1
React
Gatsby

Missing source maps for large first-party JavaScript

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

URL	Map URL
sainsburys.co.uk 1st party
/assets/app-174….js (www.sainsburys.co.uk)
Large JavaScript file is missing a source map

Ensure CSP is effective against XSS attacks

A strong Content Security Policy (CSP) significantly reduces the risk of cross-site scripting (XSS) attacks. Learn how to use a CSP to prevent XSS

Description	Directive	Severity
`script-src` directive is missing. This can allow the execution of unsafe scripts.	script-src	High
Missing `object-src` allows the injection of plugins that execute unsafe scripts. Consider setting `object-src` to `'none'` if you can.	object-src	High

Use a strong HSTS policy

Deployment of the HSTS header significantly reduces the risk of downgrading HTTP connections and eavesdropping attacks. A rollout in stages, starting with a low max-age is recommended. Learn more about using a strong HSTS policy.

Description	Directive	Severity
`max-age` is too low	max-age	High
No `preload` directive found	preload	Medium

Ensure proper origin isolation with COOP

The Cross-Origin-Opener-Policy (COOP) can be used to isolate the top-level window from other documents such as pop-ups. Learn more about deploying the COOP header.

Description	Directive	Severity
No COOP header found		High

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Uses HTTPS

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being served over HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more about HTTPS.

Avoids third-party cookies

Chrome is moving towards a new experience that allows users to choose to browse without third-party cookies. Learn more about third-party cookies.

Allows users to paste into input fields

Preventing input pasting is a bad practice for the UX, and weakens security by blocking password managers.Learn more about user-friendly input fields.

Avoids requesting the geolocation permission on page load

Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to a user action instead. Learn more about the geolocation permission.

Avoids requesting the notification permission on page load

Users are mistrustful of or confused by sites that request to send notifications without context. Consider tying the request to user gestures instead. Learn more about responsibly getting permission for notifications.

Displays images with correct aspect ratio

Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

Serves images with appropriate resolution

Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.

Has a <meta name="viewport"> tag with width or initial-scale

A <meta name="viewport"> not only optimizes your app for mobile screen sizes, but also prevents a 300 millisecond delay to user input. Learn more about using the viewport meta tag.

Document uses legible font sizes 100% legible text

Font sizes less than 12px are too small to be legible and require mobile visitors to “pinch to zoom” in order to read. Strive to have >60% of page text ≥12px. Learn more about legible font sizes.

Source	Selector	% of Page Text	Font Size
Legible text		100.00%	≥ 12px

Page has the HTML doctype

Specifying a doctype prevents the browser from switching to quirks-mode. Learn more about the doctype declaration.

Properly defines charset

A character encoding declaration is required. It can be done with a <meta> tag in the first 1024 bytes of the HTML or in the Content-Type HTTP response header. Learn more about declaring the character encoding.

No browser errors logged to the console

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

No issues in the Issues panel in Chrome Devtools

Issues logged to the Issues panel in Chrome Devtools indicate unresolved problems. They can come from network request failures, insufficient security controls, and other browser concerns. Open up the Issues panel in Chrome DevTools for more details on each issue.

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Redirects HTTP traffic to HTTPS

Make sure that you redirect all HTTP traffic to HTTPS in order to enable secure web features for all your users. Learn more.

Mitigate clickjacking with XFO or CSP

The X-Frame-Options (XFO) header or the frame-ancestors directive in the Content-Security-Policy (CSP) header control where a page can be embedded. These can mitigate clickjacking attacks by blocking some or all sites from embedding the page. Learn more about mitigating clickjacking.

100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

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Structured data is valid

Run the Structured Data Testing Tool and the Structured Data Linter to validate structured data. Learn more about Structured Data.

Run these additional validators on your site to check additional SEO best practices.

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Page isn’t blocked from indexing

Search engines are unable to include your pages in search results if they don't have permission to crawl them. Learn more about crawler directives.

Document has a <title> element

The title gives screen reader users an overview of the page, and search engine users rely on it heavily to determine if a page is relevant to their search. Learn more about document titles.

Document has a meta description

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Page has successful HTTP status code

Pages with unsuccessful HTTP status codes may not be indexed properly. Learn more about HTTP status codes.

Links have descriptive text

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Links are crawlable

Search engines may use href attributes on links to crawl websites. Ensure that the href attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable

robots.txt is valid

If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. Learn more about robots.txt.

Image elements have [alt] attributes

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the alt attribute.

Document has a valid hreflang

hreflang links tell search engines what version of a page they should list in search results for a given language or region. Learn more about hreflang.

Document has a valid rel=canonical

Canonical links suggest which URL to show in search results. Learn more about canonical links.

Values are estimated and may vary. The performance score is calculated directly from these metrics.See calculator.

0–49 50–89 90–100

First Contentful Paint

0.6 s

First Contentful Paint marks the time at which the first text or image is painted. Learn more about the First Contentful Paint metric.

Largest Contentful Paint

1.2 s

Largest Contentful Paint marks the time at which the largest text or image is painted. Learn more about the Largest Contentful Paint metric

Total Blocking Time

180 ms

Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more about the Total Blocking Time metric.

Cumulative Layout Shift

0.009

Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more about the Cumulative Layout Shift metric.

Speed Index

1.6 s

Speed Index shows how quickly the contents of a page are visibly populated. Learn more about the Speed Index metric.

Captured at Mar 10, 2025, 6:00 PM UTC
Emulated Desktop with Lighthouse 12.4.0
Unthrottled CPU/Memory Power: 520 CPU throttling: 1x slowdown (Simulated) Screen emulation: 1350x940, DPR 1 Axe version: 4.10.2
Single page session
This data is taken from a single page session, as opposed to field data summarizing many sessions.
Initial page load
Custom throttling
Network throttling: 40 ms TCP RTT, 10,240 kb/s throughput (Simulated) Browser location: North America
Using HeadlessChromium 133.0.6943.141 with lr
User agent (network): "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36"

Properly size images Potential savings of 638 KiB

Serve images that are appropriately-sized to save cellular data and improve load time. Learn how to size images.LCPFCP

Use the gatsby-plugin-image component to set appropriate sizes. Learn more.

	URL	Resource Size	Potential Savings
4rgos.it		725.7 KiB	637.6 KiB
Explore Habitat homeware. <img src="https://media.4rgos.it/i/Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp" alt="Explore Habitat homeware." data-test="component-image" loading="auto">	…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	64.2 KiB	52.3 KiB
Mother's Day. <img src="https://media.4rgos.it/i/Argos/W1_M050_couk_Mothers_day?maxW=1200&qlt=75&f…" alt="Mother's Day." data-test="component-image" loading="auto">	…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	52.4 KiB	47.1 KiB
Shop In Season. <img src="https://media.4rgos.it/i/Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp" alt="Shop In Season." data-test="component-image" loading="auto">	…Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	52.2 KiB	47.0 KiB
Large egg stunt from £2.50. <img src="https://media.4rgos.it/i/Argos/M050_Large_eggs_stunt_Couk?maxW=1200&qlt=75…" alt="Large egg stunt from £2.50." data-test="component-image" loading="auto">	…Argos/M050_Larg…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	49.0 KiB	44.1 KiB
Easter is coming. <img src="https://media.4rgos.it/i/Argos/M050_Easter_Event_Co-uk?maxW=1200&qlt=75&fm…" alt="Easter is coming." data-test="component-image" loading="auto">	…Argos/M050_East…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	48.4 KiB	43.6 KiB
Half Price Freezer Fillers. <img src="https://media.4rgos.it/i/Argos/M050_Half_price_freezer_Co-Uk_?maxW=1200&ql…" alt="Half Price Freezer Fillers." data-test="component-image" loading="auto">	…Argos/M050_Half…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	48.3 KiB	43.5 KiB
Best of British. <img src="https://media.4rgos.it/i/Argos/v2_GoodTokKow_BestOfBrtish_n_couk_topright_…" alt="Best of British." data-test="component-image" loading="auto">	…Argos/v2_GoodTo…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	45.3 KiB	40.8 KiB
Home energy that feels rewarding. <img src="https://media.4rgos.it/i/Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp" alt="Home energy that feels rewarding." data-test="component-image" loading="auto">	…Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	40.0 KiB	36.0 KiB
Ramadan. <img src="https://media.4rgos.it/i/Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp" alt="Ramadan." data-test="component-image" loading="auto">	…Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	35.9 KiB	32.3 KiB
Sainsbury’s Bank Pet Insurance. <img src="https://media.4rgos.it/i/Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp" alt="Sainsbury’s Bank Pet Insurance." data-test="component-image" loading="auto">	…Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	35.4 KiB	31.9 KiB
How we’re working towards our plan for better. <img src="https://media.4rgos.it/i/Argos/M050_co_uk_plan_for_better?maxW=1200&qlt=75…" alt="How we’re working towards our plan for better." data-test="component-image" loading="auto">	…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	35.2 KiB	31.7 KiB
Buy 3 or more bottles save 25%. <img src="https://media.4rgos.it/i/Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp" alt="Buy 3 or more bottles save 25%." data-test="component-image" loading="auto">	…Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	32.5 KiB	29.3 KiB
Book a delivery. <img src="https://media.4rgos.it/i/Argos/COO4_Delivery?w=600&poi={$this.metadata.poi…" alt="Book a delivery." data-test="c004-image-logo-main-image" loading="auto">	…Argos/COO4_Delivery?w=… (media.4rgos.it)	36.2 KiB	26.9 KiB
Donate to Comic Relief. <img src="https://media.4rgos.it/i/Argos/M050_co_uk_Comic_Relief?maxW=1200&qlt=75&fm…" alt="Donate to Comic Relief." data-test="component-image" loading="auto">	…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	29.4 KiB	26.5 KiB
New season. <img src="https://media.4rgos.it/i/Argos/0125-m050-tu-work-everytime?maxW=1200&qlt=7…" alt="New season." data-test="component-image" loading="auto">	…Argos/0125-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	27.0 KiB	22.0 KiB
Thanks Mum. <img src="https://media.4rgos.it/i/Argos/4825-m050-mothers-day?maxW=1200&qlt=75&fmt=…" alt="Thanks Mum." data-test="component-image" loading="auto">	…Argos/4825-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	22.4 KiB	18.3 KiB
Start saving more, now. <img src="https://media.4rgos.it/i/Argos/nectarsignup_js_n_nv_pl_couk_pod_1_n%20(1)?…" alt="Start saving more, now." data-test="component-image" loading="auto">	…Argos/nectarsig…%20(1)?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	19.4 KiB	17.2 KiB
Prices matched. <img src="https://media.4rgos.it/i/Argos/M050_couk_Aldi_price_match?maxW=1200&qlt=75…" alt="Prices matched." data-test="component-image" loading="auto">	…Argos/M050_couk…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	17.9 KiB	16.1 KiB
Exclusive prices on items we think you’ll love. <img src="https://media.4rgos.it/i/Argos/ynp_js_n_yournectarprices_pl_couk_banner_n_…" alt="Exclusive prices on items we think you’ll love." data-test="component-image" loading="auto">	…Argos/ynp_js_n_…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	17.4 KiB	15.7 KiB
Got Nectar? Shop lower prices. <img src="https://media.4rgos.it/i/Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp" alt="Got Nectar? Shop lower prices." data-test="component-image" loading="auto">	…Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	17.1 KiB	15.4 KiB

Defer offscreen images Potential savings of 487 KiB

Consider lazy-loading offscreen and hidden images after all critical resources have finished loading to lower time to interactive. Learn how to defer offscreen images.LCPFCP

Use the gatsby-plugin-image component instead of <img> to automatically lazy-load images. Learn more.

	URL	Resource Size	Potential Savings
4rgos.it		442.1 KiB	442.1 KiB
platter of sandwiches <img src="https://media.4rgos.it/i/Argos/Sandwich%20GOL?w=600&poi={$this.metadata.po…" alt="platter of sandwiches " data-test="c004-image-logo-main-image" loading="auto">	…Argos/Sandwich%20GOL?w=… (media.4rgos.it)	47.6 KiB	47.6 KiB
Shop In-Season. <img src="https://media.4rgos.it/i/Argos/v2_C004_Shop_In_Season?w=600&poi={$this.met…" alt="Shop In-Season." data-test="c004-image-logo-main-image" loading="auto">	…Argos/v2_C004_S…?w=… (media.4rgos.it)	44.3 KiB	44.3 KiB
Feed your family for a fiver. <img src="https://media.4rgos.it/i/Argos/C004_feed_your_family?w=600&poi={$this.meta…" alt="Feed your family for a fiver." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_feed…?w=… (media.4rgos.it)	37.9 KiB	37.9 KiB
Meat Free Monday. <img src="https://media.4rgos.it/i/Argos/C004_meat_free_monday?w=600&poi={$this.meta…" alt="Meat Free Monday." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_meat…?w=… (media.4rgos.it)	35.7 KiB	35.7 KiB
New arrivals at habitat. <img src="https://media.4rgos.it/i/Argos/0724-600-300-habitat-3265660?w=600&poi={$th…" alt="New arrivals at habitat." data-test="c004-image-logo-main-image" loading="auto">	…Argos/0724-600-…?w=… (media.4rgos.it)	33.5 KiB	33.5 KiB
Budget Friendly. <img src="https://media.4rgos.it/i/Argos/C004_budget_friendly?w=600&poi={$this.metad…" alt="Budget Friendly." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_budg…?w=… (media.4rgos.it)	33.1 KiB	33.1 KiB
Taste the Difference. <img src="https://media.4rgos.it/i/Argos/v2_C004_TTD_Hub?w=600&poi={$this.metadata.p…" alt="Taste the Difference." data-test="c004-image-logo-main-image" loading="auto">	…Argos/v2_C004_TTD_Hub?w=… (media.4rgos.it)	27.1 KiB	27.1 KiB
Women in striped pink pyjama set <img src="https://media.4rgos.it/i/Argos/image_New_TU_24?w=600&poi={$this.metadata.p…" alt="Women in striped pink pyjama set" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image_New_TU_24?w=… (media.4rgos.it)	19.8 KiB	19.8 KiB
Shop Habitat 60th celebration. <img src="https://media.4rgos.it/i/Argos/Habitat_meganav?w=600&poi={$this.metadata.p…" alt="Shop Habitat 60th celebration." data-test="c004-image-logo-main-image" loading="auto">	…Argos/Habitat_meganav?w=… (media.4rgos.it)	19.6 KiB	19.6 KiB
Shop spring homeware edit. <img src="https://media.4rgos.it/i/Argos/0724-600-300-habitat-candle?w=600&poi={$thi…" alt="Shop spring homeware edit." data-test="c004-image-logo-main-image" loading="auto">	…Argos/0724-600-…?w=… (media.4rgos.it)	16.8 KiB	16.8 KiB
Woman on sofa hugging her daughter. <img src="https://media.4rgos.it/i/Argos/JS_Landing_Page_Dropdown_600x300px%20(002)?…" alt="Woman on sofa hugging her daughter." data-test="c004-image-logo-main-image" loading="auto">	…Argos/JS_Landin…%20(002)?w=… (media.4rgos.it)	15.8 KiB	15.8 KiB
100% renewable electricity* <img src="https://media.4rgos.it/i/Argos/couk_dropdown_energy?w=600&poi={$this.metad…" alt="100% renewable electricity*" data-test="c004-image-logo-main-image" loading="auto">	…Argos/couk_drop…?w=… (media.4rgos.it)	14.2 KiB	14.2 KiB
Sainsbury's Bank Travel Money. <img src="https://media.4rgos.it/i/Argos/MAR002711-021%20JS%20drop%20down%20225%20x%…" alt="Sainsbury's Bank Travel Money." data-test="c004-image-logo-main-image" loading="auto">	…Argos/MAR002711-021%20JS%20drop%20down%20225%20x%20124px?w=… (media.4rgos.it)	13.6 KiB	13.6 KiB
Cake on cake stand <img src="https://media.4rgos.it/i/Argos/Cake%20GOL?w=600&poi={$this.metadata.pointO…" alt="Cake on cake stand" data-test="c004-image-logo-main-image" loading="auto">	…Argos/Cake%20GOL?w=… (media.4rgos.it)	12.9 KiB	12.9 KiB
Girl in white fleece pyjama set <img src="https://media.4rgos.it/i/Argos/image2_New_TU_24?w=600&poi={$this.metadata.…" alt="Girl in white fleece pyjama set" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image2_New_TU_24?w=… (media.4rgos.it)	12.9 KiB	12.9 KiB
construction toy <img src="https://media.4rgos.it/i/Argos/sb-1422-225x150-argos-toyoffers?w=600&poi={…" alt="construction toy" data-test="c004-image-logo-main-image" loading="auto">	…Argos/sb-1422-2…?w=… (media.4rgos.it)	11.8 KiB	11.8 KiB
Man in green pyjama set <img src="https://media.4rgos.it/i/Argos/image1_New_TU_24?w=600&poi={$this.metadata.…" alt="Man in green pyjama set" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image1_New_TU_24?w=… (media.4rgos.it)	10.7 KiB	10.7 KiB
Man in green hoodie hugging a dog. <img src="https://media.4rgos.it/i/Argos/SB6935_MAR002981-007_Q4_2024_Pet_JS_Dropdow…" alt="Man in green hoodie hugging a dog." data-test="c004-image-logo-main-image" loading="auto">	…Argos/SB6935_MA…?w=… (media.4rgos.it)	9.8 KiB	9.8 KiB
Woman in pyjama set with stay cosy slogan <img src="https://media.4rgos.it/i/Argos/image3_New_TU_24?w=600&poi={$this.metadata.…" alt="Woman in pyjama set with stay cosy slogan" data-test="c004-image-logo-main-image" loading="auto">	…Argos/image3_New_TU_24?w=… (media.4rgos.it)	6.9 KiB	6.9 KiB
Discover Nectar Prices. <img src="https://media.4rgos.it/i/Argos/v2_Discover_nectar_C004?w=600&poi={$this.me…" alt="Discover Nectar Prices." data-test="c004-image-logo-main-image" loading="auto">	…Argos/v2_Discov…?w=… (media.4rgos.it)	6.9 KiB	6.9 KiB
New In. <img src="https://media.4rgos.it/i/Argos/2123-225x150-ddn-argos-newin-3100567-303348…" alt="New In." data-test="c004-image-logo-main-image" loading="auto">	…Argos/2123-225x…?w=… (media.4rgos.it)	6.4 KiB	6.4 KiB
Clearance <img src="https://media.4rgos.it/i/Argos/sb-1422-225x150-argos-clearance?w=600&poi={…" alt="Clearance" data-test="c004-image-logo-main-image" loading="auto">	…Argos/sb-1422-2…?w=… (media.4rgos.it)	4.9 KiB	4.9 KiB
Optanon consent-provider		27.8 KiB	27.8 KiB
Company Logo <img alt="Company Logo" src="https://cdn-ukwest.onetrust.com/logos/e1fd2f29-c8cd-4679-82e1-451d39f5ae8a…">	…53f3532a-319c-45d4-b6eb-3922b10c275d/sainsburys.png (cdn-ukwest.onetrust.com)	25.0 KiB	25.0 KiB
Powered by Onetrust <img alt="Powered by Onetrust" src="https://cdn-ukwest.onetrust.com/logos/static/powered_by_logo.svg">	…static/powered_by_logo.svg (cdn-ukwest.onetrust.com)	2.8 KiB	2.8 KiB
Unattributable		16.7 KiB	16.7 KiB
Get it on Google Play <img src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9z…" alt="Get it on Google Play" width="135" height="40" data-testid="sainsburys-google-play-logo" class="Appsstyles__AppsImage-sc-15fzq3m-6 bxlJZa">	data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vc…	9.5 KiB	9.5 KiB
Download on the app store <img src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9z…" alt="Download on the app store" width="119" height="40" data-testid="sainsburys-app-store-logo" class="Appsstyles__AppsImage-sc-15fzq3m-6 bxlJZa">	data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vc…	7.2 KiB	7.2 KiB

Reduce unused JavaScript Potential savings of 522 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.LCPFCP

Use Webpack Bundle Analyzer to detect unused JavaScript code. Learn more

If you are not server-side rendering, split your JavaScript bundles with React.lazy(). Otherwise, code-split using a third-party library such as loadable-components.

URL	Transfer Size	Potential Savings
sainsburys.co.uk 1st party	517.4 KiB	288.2 KiB
/assets/app-174….js (www.sainsburys.co.uk)	402.6 KiB	231.9 KiB
/assets/120fac23-174….js (www.sainsburys.co.uk)	114.7 KiB	56.3 KiB
Google Tag Manager tag-manager	289.0 KiB	132.3 KiB
/gtag/js?id=… (www.googletagmanager.com)	135.5 KiB	54.3 KiB
/gtag/js?id=… (www.googletagmanager.com)	94.3 KiB	42.8 KiB
/gtag/js (www.googletagmanager.com)	59.2 KiB	35.2 KiB
Optanon consent-provider	112.4 KiB	61.0 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	112.4 KiB	61.0 KiB
Tealium tag-manager	84.2 KiB	40.6 KiB
…prod/utag.js (tags.tiqcdn.com)	84.2 KiB	40.6 KiB

Largest Contentful Paint element 1,250 ms

This is the largest contentful element painted within the viewport. Learn more about the Largest Contentful Paint elementLCP

Element
Got Nectar? Shop lower prices. <img src="https://media.4rgos.it/i/Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp" alt="Got Nectar? Shop lower prices." data-test="component-image" loading="auto">

Phase	% of LCP	Timing
TTFB	13%	160 ms
Load Delay	54%	670 ms
Load Time	14%	170 ms
Render Delay	20%	250 ms

Eliminate render-blocking resources Potential savings of 150 ms

Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles. Learn how to eliminate render-blocking resources.LCPFCP

Use the Gatsby Script API to defer loading of non-critical third-party scripts. Learn more.

URL	Transfer Size	Potential Savings
Tealium tag-manager	1.1 KiB	200 ms
…prod/utag.sync.js (tags.tiqcdn.com)	1.1 KiB	200 ms

Image elements do not have explicit width and height

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensionsCLS

	URL
4rgos.it
Book your click and collect. <img src="https://media.4rgos.it/i/Argos/C004_click_and_collect?w=600&poi={$this.met…" alt="Book your click and collect." data-test="c004-image-logo-main-image" loading="auto">	…Argos/C004_clic…?w=… (media.4rgos.it)
Book a delivery. <img src="https://media.4rgos.it/i/Argos/COO4_Delivery?w=600&poi={$this.metadata.poi…" alt="Book a delivery." data-test="c004-image-logo-main-image" loading="auto">	…Argos/COO4_Delivery?w=… (media.4rgos.it)
Sainsbury's Chop Chop app. <img src="https://media.4rgos.it/i/Argos/COO4_Chop_Chop?w=600&poi={$this.metadata.po…" alt="Sainsbury's Chop Chop app." data-test="c004-image-logo-main-image" loading="auto">	…Argos/COO4_Chop_Chop?w=… (media.4rgos.it)
Sainsbury's Delivery Pass. <img src="https://media.4rgos.it/i/Argos/W1_C004_Delivery_Pass?w=600&poi={$this.meta…" alt="Sainsbury's Delivery Pass." data-test="c004-image-logo-main-image" loading="auto">	…Argos/W1_C004_D…?w=… (media.4rgos.it)

Serve images in next-gen formats Potential savings of 50 KiB

Image formats like WebP and AVIF often provide better compression than PNG or JPEG, which means faster downloads and less data consumption. Learn more about modern image formats.LCPFCP

Use the gatsby-plugin-image component instead of <img> to automatically optimize image format. Learn more.

URL	Resource Size	Potential Savings
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAe4AAAD6CAYAAABnJ…	34.4 KiB	25.3 KiB
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAfMAAAGmCAYAAABoT…	22.9 KiB	14.7 KiB
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAfIAAADiCAYAAAC1M…	14.8 KiB	9.8 KiB

Serve static assets with an efficient cache policy 56 resources found

A long cache lifetime can speed up repeat visits to your page. Learn more about efficient cache policies.

Configure caching for immutable assets. Learn more.

URL	Cache TTL	Transfer Size
4rgos.it		1,227 KiB
…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	65 KiB
…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	53 KiB
…Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	53 KiB
…Argos/M050_Larg…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	50 KiB
…Argos/M050_East…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	49 KiB
…Argos/M050_Half…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	49 KiB
…Argos/Sandwich%20GOL?w=… (media.4rgos.it)	30m	48 KiB
…Argos/v2_GoodTo…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	46 KiB
…Argos/v2_C004_S…?w=… (media.4rgos.it)	30m	45 KiB
…Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	40 KiB
…Argos/C004_feed…?w=… (media.4rgos.it)	30m	38 KiB
…Argos/COO4_Delivery?w=… (media.4rgos.it)	30m	37 KiB
…Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	36 KiB
…Argos/C004_meat…?w=… (media.4rgos.it)	30m	36 KiB
…Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	36 KiB
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	36 KiB
…Argos/0724-600-…?w=… (media.4rgos.it)	30m	34 KiB
…Argos/C004_budg…?w=… (media.4rgos.it)	30m	34 KiB
…Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	33 KiB
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	30 KiB
…Argos/v2_C004_TTD_Hub?w=… (media.4rgos.it)	30m	28 KiB
…Argos/0125-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	28 KiB
…Argos/4825-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	23 KiB
…Argos/image_New_TU_24?w=… (media.4rgos.it)	30m	20 KiB
…Argos/Habitat_meganav?w=… (media.4rgos.it)	30m	20 KiB
…Argos/nectarsig…%20(1)?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	20 KiB
…Argos/M050_couk…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	18 KiB
…Argos/ynp_js_n_…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	18 KiB
…Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30m	18 KiB
…Argos/0724-600-…?w=… (media.4rgos.it)	30m	17 KiB
…Argos/JS_Landin…%20(002)?w=… (media.4rgos.it)	30m	16 KiB
…Argos/W1_C004_D…?w=… (media.4rgos.it)	30m	15 KiB
…Argos/couk_drop…?w=… (media.4rgos.it)	30m	15 KiB
…Argos/MAR002711-021%20JS%20drop%20down%20225%20x%20124px?w=… (media.4rgos.it)	30m	14 KiB
…Argos/C004_clic…?w=… (media.4rgos.it)	30m	14 KiB
…Argos/Cake%20GOL?w=… (media.4rgos.it)	30m	13 KiB
…Argos/image2_New_TU_24?w=… (media.4rgos.it)	30m	13 KiB
…Argos/sb-1422-2…?w=… (media.4rgos.it)	30m	12 KiB
…Argos/image1_New_TU_24?w=… (media.4rgos.it)	30m	11 KiB
…Argos/SB6935_MA…?w=… (media.4rgos.it)	30m	10 KiB
…Argos/COO4_Chop_Chop?w=… (media.4rgos.it)	30m	10 KiB
…Argos/image3_New_TU_24?w=… (media.4rgos.it)	30m	7 KiB
…Argos/v2_Discov…?w=… (media.4rgos.it)	30m	7 KiB
…Argos/2123-225x…?w=… (media.4rgos.it)	30m	7 KiB
…Argos/sb-1422-2…?w=… (media.4rgos.it)	30m	5 KiB
Optanon consent-provider		150 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	1d	113 KiB
…53f3532a-319c-45d4-b6eb-3922b10c275d/sainsburys.png (cdn-ukwest.onetrust.com)	1d	26 KiB
/scripttemplates/otSDKStub.js (cdn-ukwest.onetrust.com)	1d	8 KiB
…static/powered_by_logo.svg (cdn-ukwest.onetrust.com)	1d	3 KiB
Tealium tag-manager		103 KiB
…prod/utag.js (tags.tiqcdn.com)	5m	85 KiB
…prod/utag.351.js?utv=ut4.44.202… (tags.tiqcdn.com)	5m	10 KiB
…prod/utag.282.js?utv=ut4.44.202… (tags.tiqcdn.com)	5m	3 KiB
…prod/utag.289.js?utv=ut4.44.202… (tags.tiqcdn.com)	5m	3 KiB
…prod/utag.sync.js (tags.tiqcdn.com)	5m	1 KiB
…tiqapp/utag.v.js?a=sainsburys/groceries/202…&cb=174… (tags.tiqcdn.com)	5m	1 KiB
New Relic utility		1 KiB
/1/d471046ff6?a=… (bam.nr-data.net)	None	1 KiB

Avoid serving legacy JavaScript to modern browsers Potential savings of 13 KiB

URL		Potential Savings
Optanon consent-provider		7.2 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)		7.2 KiB
…202501.1.0/otBannerSdk.js:7:7428 (cdn-ukwest.onetrust.com)	Array.prototype.fill
Tealium tag-manager		5.8 KiB
…prod/utag.js (tags.tiqcdn.com)		5.8 KiB
…prod/utag.js:363:268 (tags.tiqcdn.com)	Date.now
sainsburys.co.uk 1st party		0.1 KiB
/assets/app-174….js (www.sainsburys.co.uk)		0.1 KiB
/assets/app-174….js:14:5482 (www.sainsburys.co.uk)	@babel/plugin-transform-classes

Reduce unused CSS Potential savings of 96 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.LCPFCP

Use the PurgeCSS Gatsby plugin to remove unused rules from stylesheets. Learn more.

URL	Transfer Size	Potential Savings
:export{color_primary:#375ea9;color_primary_light:#e7eff7;color_primary_dark:#08305f;color_secondar…	84.2 KiB	78.4 KiB
#onetrust-banner-sdk .onetrust-vendors-list-handler{cursor:pointer;color:#1f96db;font-size:inherit; … } …	20.6 KiB	17.7 KiB

URL

Transfer Size

Potential Savings

:export{color_primary:#375ea9;color_primary_light:#e7eff7;color_primary_dark:#08305f;color_secondar…

84.2 KiB

78.4 KiB

#onetrust-banner-sdk .onetrust-vendors-list-handler{cursor:pointer;color:#1f96db;font-size:inherit; … } …

20.6 KiB

17.7 KiB

Avoid enormous network payloads Total size was 2,671 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

URL	Transfer Size
sainsburys.co.uk 1st party	687.6 KiB
/assets/app-174….js (www.sainsburys.co.uk)	403.9 KiB
https://www.sainsburys.co.uk	167.8 KiB
/assets/120fac23-174….js (www.sainsburys.co.uk)	115.9 KiB
Google Tag Manager tag-manager	292.2 KiB
/gtag/js?id=… (www.googletagmanager.com)	136.6 KiB
/gtag/js?id=… (www.googletagmanager.com)	95.3 KiB
/gtag/js (www.googletagmanager.com)	60.3 KiB
4rgos.it	117.5 KiB
…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	64.7 KiB
…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	52.8 KiB
Optanon consent-provider	113.4 KiB
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	113.4 KiB
Tealium tag-manager	84.8 KiB
…prod/utag.js (tags.tiqcdn.com)	84.8 KiB

Avoid an excessive DOM size 1,064 elements

A large DOM will increase memory usage, cause longer style calculations, and produce costly layout reflows. Learn how to avoid an excessive DOM size.TBT

Statistic	Element	Value
Total DOM Elements		1,064
Maximum DOM Depth	div.Rowstyles__GridRow-sc-1w6itvg-0 > div.ImageCtaCardstyles__StyledImageContainer-sc-1jyhigy-1 > picture > source <source type="image/webp" srcset="//media.4rgos.it/i/Argos/v2_Discover_nectar_C004?w=600&poi={$this.metadata…">	19
Maximum Child Elements	body <body>	14

Avoid long main-thread tasks 7 long tasks found

Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay. Learn how to avoid long main-thread tasksTBT

URL	Start Time	Duration
sainsburys.co.uk 1st party		363 ms
/assets/1775ce01-174….js (www.sainsburys.co.uk)	2,639 ms	158 ms
/assets/1775ce01-174….js (www.sainsburys.co.uk)	2,797 ms	116 ms
/assets/framework-174….js (www.sainsburys.co.uk)	2,550 ms	89 ms
Google Tag Manager tag-manager		165 ms
/gtag/js?id=… (www.googletagmanager.com)	2,114 ms	110 ms
/gtag/js?id=… (www.googletagmanager.com)	1,554 ms	55 ms
Unattributable		67 ms
Unattributable	543 ms	67 ms
Tealium tag-manager		62 ms
…prod/utag.js (tags.tiqcdn.com)	848 ms	62 ms

Minimize third-party usage Third-party code blocked the main thread for 80 ms

Third-Party	Transfer Size	Main-Thread Blocking Time
Google Tag Manager tag-manager	292 KiB	65 ms
/gtag/js?id=… (www.googletagmanager.com)	137 KiB	60 ms
/gtag/js?id=… (www.googletagmanager.com)	95 KiB	5 ms
/gtag/js (www.googletagmanager.com)	60 KiB	0 ms
Tealium tag-manager	103 KiB	12 ms
…prod/utag.js (tags.tiqcdn.com)	85 KiB	12 ms
…prod/utag.351.js?utv=ut4.44.202… (tags.tiqcdn.com)	10 KiB	0 ms
…prod/utag.282.js?utv=ut4.44.202… (tags.tiqcdn.com)	3 KiB	0 ms
…prod/utag.289.js?utv=ut4.44.202… (tags.tiqcdn.com)	3 KiB	0 ms
…prod/utag.sync.js (tags.tiqcdn.com)	1 KiB	0 ms
…tiqapp/utag.v.js?a=sainsburys/groceries/202…&cb=174… (tags.tiqcdn.com)	1 KiB	0 ms
4rgos.it	1,227 KiB	0 ms
…Argos/M050_couk_Habitat?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	65 KiB	0 ms
…Argos/W1_M050_c…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	53 KiB	0 ms
…Argos/M053_In_season?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	53 KiB	0 ms
…Argos/M050_Larg…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	50 KiB	0 ms
…Argos/M050_East…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	49 KiB	0 ms
…Argos/M050_Half…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	49 KiB	0 ms
…Argos/Sandwich%20GOL?w=… (media.4rgos.it)	48 KiB	0 ms
…Argos/v2_GoodTo…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	46 KiB	0 ms
…Argos/v2_C004_S…?w=… (media.4rgos.it)	45 KiB	0 ms
…Argos/Energy_week%2033?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	40 KiB	0 ms
…Argos/C004_feed…?w=… (media.4rgos.it)	38 KiB	0 ms
…Argos/COO4_Delivery?w=… (media.4rgos.it)	37 KiB	0 ms
…Argos/Ramadan_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	36 KiB	0 ms
…Argos/C004_meat…?w=… (media.4rgos.it)	36 KiB	0 ms
…Argos/JS%20Pet%20Pod_V2?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	36 KiB	0 ms
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	36 KiB	0 ms
…Argos/0724-600-…?w=… (media.4rgos.it)	34 KiB	0 ms
…Argos/C004_budg…?w=… (media.4rgos.it)	34 KiB	0 ms
…Argos/W1_Buy_3_M050_couk?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	33 KiB	0 ms
…Argos/M050_co_u…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	30 KiB	0 ms
…Argos/v2_C004_TTD_Hub?w=… (media.4rgos.it)	28 KiB	0 ms
…Argos/0125-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	28 KiB	0 ms
…Argos/4825-m050…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	23 KiB	0 ms
…Argos/image_New_TU_24?w=… (media.4rgos.it)	20 KiB	0 ms
…Argos/Habitat_meganav?w=… (media.4rgos.it)	20 KiB	0 ms
…Argos/nectarsig…%20(1)?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	20 KiB	0 ms
…Argos/M050_couk…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	18 KiB	0 ms
…Argos/ynp_js_n_…?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	18 KiB	0 ms
…Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp (media.4rgos.it)	18 KiB	0 ms
…Argos/0724-600-…?w=… (media.4rgos.it)	17 KiB	0 ms
…Argos/JS_Landin…%20(002)?w=… (media.4rgos.it)	16 KiB	0 ms
…Argos/W1_C004_D…?w=… (media.4rgos.it)	15 KiB	0 ms
…Argos/couk_drop…?w=… (media.4rgos.it)	15 KiB	0 ms
…Argos/MAR002711-021%20JS%20drop%20down%20225%20x%20124px?w=… (media.4rgos.it)	14 KiB	0 ms
…Argos/C004_clic…?w=… (media.4rgos.it)	14 KiB	0 ms
…Argos/Cake%20GOL?w=… (media.4rgos.it)	13 KiB	0 ms
…Argos/image2_New_TU_24?w=… (media.4rgos.it)	13 KiB	0 ms
…Argos/sb-1422-2…?w=… (media.4rgos.it)	12 KiB	0 ms
…Argos/image1_New_TU_24?w=… (media.4rgos.it)	11 KiB	0 ms
…Argos/SB6935_MA…?w=… (media.4rgos.it)	10 KiB	0 ms
…Argos/COO4_Chop_Chop?w=… (media.4rgos.it)	10 KiB	0 ms
…Argos/image3_New_TU_24?w=… (media.4rgos.it)	7 KiB	0 ms
…Argos/v2_Discov…?w=… (media.4rgos.it)	7 KiB	0 ms
…Argos/2123-225x…?w=… (media.4rgos.it)	7 KiB	0 ms
…Argos/sb-1422-2…?w=… (media.4rgos.it)	5 KiB	0 ms
Optanon consent-provider	199 KiB	0 ms
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	113 KiB	0 ms
…53f3532a-319c-45d4-b6eb-3922b10c275d/sainsburys.png (cdn-ukwest.onetrust.com)	26 KiB	0 ms
…0193644a-194e-7364-a9db-7dc86b85eecd/en.json (cdn-ukwest.onetrust.com)	22 KiB	0 ms
…v2/otPcCenter.json (cdn-ukwest.onetrust.com)	13 KiB	0 ms
/scripttemplates/otSDKStub.js (cdn-ukwest.onetrust.com)	8 KiB	0 ms
…assets/otCommonStyles.css (cdn-ukwest.onetrust.com)	5 KiB	0 ms
…assets/otFlat.json (cdn-ukwest.onetrust.com)	4 KiB	0 ms
…static/powered_by_logo.svg (cdn-ukwest.onetrust.com)	3 KiB	0 ms
…53f3532a-319c-45d4-b6eb-3922b10c275d/53f3532a-319c-45d4-b….json (cdn-ukwest.onetrust.com)	2 KiB	0 ms
…static/ot_guard_logo.svg (cdn-ukwest.onetrust.com)	1 KiB	0 ms
…geo/location (geolocation.onetrust.com)	0 KiB	0 ms
New Relic utility	19 KiB	0 ms
/nr-spa-1216.min.js (js-agent.newrelic.com)	18 KiB	0 ms
/1/d471046ff6?a=… (bam.nr-data.net)	1 KiB	0 ms
…1/d471046ff6?a=… (bam.nr-data.net)	0 KiB	0 ms
Google/Doubleclick Ads ad	2 KiB	0 ms
…activity/src=9427595;type=saigo;cat=cat_golp;ord=719…;npa=1;gd… (ade.googlesyndication.com)	1 KiB	0 ms
…activity/src=9427595;dc_pre=CKOz3YOMg…;type=saigo;cat=cat_golp… (ade.googlesyndication.com)	1 KiB	0 ms
/ccm/collect?en=… (pagead2.googlesyndication.com)	0 KiB	0 ms
Google Analytics analytics	1 KiB	0 ms
/g/collect?v=… (www.google-analytics.com)	1 KiB	0 ms

Avoid large layout shifts 1 layout shift found

Element	Layout shift score
Ways to shop with us at Sainsbury's Book your click and collect *T&Cs apply … <section>	0.009
Download on the app store <img src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9z…" alt="Download on the app store" width="119" height="40" data-testid="sainsburys-app-store-logo" class="Appsstyles__AppsImage-sc-15fzq3m-6 bxlJZa">	Media element lacking an explicit size

Avoid non-composited animations 1 animated element found

Animations which are not composited can be janky and increase CLS. Learn how to avoid non-composited animationsCLS

Element	Name
Cookie Settings <a id="ot-sdk-btn" class="FooterLegalsstyles__ListHorizontalLinks-sc-1pjsnrc-2 kSmSif ot-sdk-show-se…" href="#" data-action="footer" data-label="Cookie Settings" data-position="footer,5,4" data-testid="footer.legals.cookie.preference">
Unsupported CSS Property: color	color

Avoid chaining critical requests 3 chains found

Maximum critical path latency: 1,001.829 ms

Initial Navigation

https://www.sainsburys.co.uk

…static/mary_ann-regular-c01a3f1….woff2

(www.sainsburys.co.uk)

- 505.964 ms, 28.18 KiB

…static/mary_ann-extrabold-39e9c61….woff2

(www.sainsburys.co.uk)

- 529.15 ms, 29.30 KiB

…prod/utag.sync.js

(tags.tiqcdn.com)

- 12.074 ms, 1.11 KiB

More information about the performance of your application. These numbers don't directly affect the Performance score.

Show Hide

Minify CSS

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.LCPFCP

If your build system minifies CSS files automatically, ensure that you are deploying the production build of your application. You can check this with the React Developer Tools extension. Learn more.

Minify JavaScript

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.LCPFCP

If your build system minifies JS files automatically, ensure that you are deploying the production build of your application. You can check this with the React Developer Tools extension. Learn more.

Efficiently encode images

Optimized images load faster and consume less cellular data. Learn how to efficiently encode images.LCPFCP

Use the gatsby-plugin-image component instead of <img> to adjust image quality. Learn more.

Enable text compression

Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes. Learn more about text compression.LCPFCP

Preconnect to required origins

Consider adding preconnect or dns-prefetch resource hints to establish early connections to important third-party origins. Learn how to preconnect to required origins.LCPFCP

Initial server response time was short Root document took 230 ms

Keep the server response time for the main document short because all other requests depend on it. Learn more about the Time to First Byte metric.LCPFCP

URL	Time Spent
sainsburys.co.uk 1st party	230 ms
https://www.sainsburys.co.uk	230 ms

Avoid multiple page redirects

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.LCPFCP

If you are using React Router, minimize usage of the <Redirect> component for route navigations.

Use video formats for animated content

Remove duplicate modules in JavaScript bundles

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity. LCPFCP

Preload Largest Contentful Paint image

If the LCP element is dynamically added to the page, you should preload the image in order to improve LCP. Learn more about preloading LCP elements.LCP

Use the gatsby-plugin-image component and set the loading prop to eager. Learn more.

User Timing marks and measures

Consider instrumenting your app with the User Timing API to measure your app's real-world performance during key user experiences. Learn more about User Timing marks.

Use the React DevTools Profiler, which makes use of the Profiler API, to measure the rendering performance of your components. Learn more.

JavaScript execution time 0.8 s

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.TBT

URL	Total CPU Time	Script Evaluation	Script Parse
sainsburys.co.uk 1st party	679 ms	462 ms	7 ms
/assets/1775ce01-174….js (www.sainsburys.co.uk)	293 ms	291 ms	2 ms
https://www.sainsburys.co.uk	253 ms	43 ms	3 ms
/assets/framework-174….js (www.sainsburys.co.uk)	132 ms	128 ms	2 ms
Unattributable	235 ms	34 ms	0 ms
Unattributable	235 ms	34 ms	0 ms
Google Tag Manager tag-manager	169 ms	148 ms	12 ms
/gtag/js?id=… (www.googletagmanager.com)	113 ms	97 ms	7 ms
/gtag/js?id=… (www.googletagmanager.com)	56 ms	51 ms	5 ms
Optanon consent-provider	92 ms	61 ms	8 ms
…202501.1.0/otBannerSdk.js (cdn-ukwest.onetrust.com)	92 ms	61 ms	8 ms
Tealium tag-manager	66 ms	58 ms	6 ms
…prod/utag.js (tags.tiqcdn.com)	66 ms	58 ms	6 ms

Minimizes main-thread work 1.4 s

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread workTBT

Category	Time Spent
Script Evaluation	836 ms
Other	161 ms
Style & Layout	118 ms
Garbage Collection	94 ms
Script Parsing & Compilation	74 ms
Parse HTML & CSS	41 ms
Rendering	37 ms

All text remains visible during webfont loads

Leverage the font-display CSS feature to ensure text is user-visible while webfonts are loading. Learn more about font-display.

Lazy load third-party resources with facades

Some third-party embeds can be lazy loaded. Consider replacing them with a facade until they are required. Learn how to defer third-parties with a facade.TBT

Largest Contentful Paint image was not lazily loaded

Above-the-fold images that are lazily loaded render later in the page lifecycle, which can delay the largest contentful paint. Learn more about optimal lazy loading.LCP

Element
Got Nectar? Shop lower prices. <img src="https://media.4rgos.it/i/Argos/M050_couk_Nectar?maxW=1200&qlt=75&fmt=webp" alt="Got Nectar? Shop lower prices." data-test="component-image" loading="auto">

Uses passive listeners to improve scrolling performance

Consider marking your touch and wheel event listeners as passive to improve your page's scroll performance. Learn more about adopting passive event listeners.

Avoids document.write()

For users on slow connections, external scripts dynamically injected via document.write() can delay page load by tens of seconds. Learn how to avoid document.write().

Has a <meta name="viewport"> tag with width or initial-scale

A <meta name="viewport"> not only optimizes your app for mobile screen sizes, but also prevents a 300 millisecond delay to user input. Learn more about using the viewport meta tag.

Accessibility

Background and foreground colors do not have a sufficient contrast ratio.

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
Manage preferences <button id="onetrust-pc-btn-handler" class="cookie-setting-link">
Continue without accepting <button id="onetrust-reject-all-handler">
Accept all <button id="onetrust-accept-btn-handler">

These are opportunities to improve the legibility of your content.

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Interactive controls are keyboard focusable

Custom interactive controls are keyboard focusable and display a focus indicator. Learn how to make custom controls focusable.

Interactive elements indicate their purpose and state

Interactive elements, such as links and buttons, should indicate their state and be distinguishable from non-interactive elements. Learn how to decorate interactive elements with affordance hints.

The page has a logical tab order

Tabbing through the page follows the visual layout. Users cannot focus elements that are offscreen. Learn more about logical tab ordering.

Visual order on the page follows DOM order

DOM order matches the visual order, improving navigation for assistive technology. Learn more about DOM and visual ordering.

User focus is not accidentally trapped in a region

A user can tab into and out of any control or region without accidentally trapping their focus. Learn how to avoid focus traps.

The user's focus is directed to new content added to the page

If new content, such as a dialog, is added to the page, the user's focus is directed to it. Learn how to direct focus to new content.

HTML5 landmark elements are used to improve navigation

Landmark elements (<main>, <nav>, etc.) are used to improve the keyboard navigation of the page for assistive technology. Learn more about landmark elements.

Offscreen content is hidden from assistive technology

Offscreen content is hidden with display: none or aria-hidden=true. Learn how to properly hide offscreen content.

Custom controls have associated labels

Custom interactive controls have associated labels, provided by aria-label or aria-labelledby. Learn more about custom controls and labels.

Custom controls have ARIA roles

Custom interactive controls have appropriate ARIA roles. Learn how to add roles to custom controls.

These items address areas which an automated testing tool cannot cover. Learn more in our guide on conducting an accessibility review.

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[aria-*] attributes match their roles

Each ARIA role supports a specific subset of aria-* attributes. Mismatching these invalidates the aria-* attributes. Learn how to match ARIA attributes to their roles.

[aria-hidden="true"] is not present on the document <body>

Assistive technologies, like screen readers, work inconsistently when aria-hidden="true" is set on the document <body>. Learn how aria-hidden affects the document body.

[role]s have all required [aria-*] attributes

Some ARIA roles have required attributes that describe the state of the element to screen readers. Learn more about roles and required attributes.

[aria-*] attributes have valid values

Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more about valid values for ARIA attributes.

[aria-*] attributes are valid and not misspelled

Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid names. Learn more about valid ARIA attributes.

Buttons have an accessible name

When a button doesn't have an accessible name, screen readers announce it as "button", making it unusable for users who rely on screen readers. Learn how to make buttons more accessible.

Image elements have [alt] attributes

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the alt attribute.

[user-scalable="no"] is not used in the <meta name="viewport"> element and the [maximum-scale] attribute is not less than 5.

Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.

ARIA attributes are used as specified for the element's role

Some ARIA attributes are only allowed on an element under certain conditions. Learn more about conditional ARIA attributes.

Elements with role="dialog" or role="alertdialog" have accessible names.

ARIA dialog elements without accessible names may prevent screen readers users from discerning the purpose of these elements. Learn how to make ARIA dialog elements more accessible.

[aria-hidden="true"] elements do not contain focusable descendents

Elements use only permitted ARIA attributes

Using ARIA attributes in roles where they are prohibited can mean that important information is not communicated to users of assistive technologies. Learn more about prohibited ARIA roles.

[role] values are valid

ARIA roles must have valid values in order to perform their intended accessibility functions. Learn more about valid ARIA roles.

Document has a <title> element

The title gives screen reader users an overview of the page, and search engine users rely on it heavily to determine if a page is relevant to their search. Learn more about document titles.

<html> element has a [lang] attribute

<html> element has a valid value for its [lang] attribute

Specifying a valid BCP 47 language helps screen readers announce text properly. Learn how to use the lang attribute.

Form elements have associated labels

Labels ensure that form controls are announced properly by assistive technologies, like screen readers. Learn more about form element labels.

Links are distinguishable without relying on color.

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Links have a discernible name

Lists contain only <li> elements and script supporting elements (<script> and <template>).

Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. Learn more about proper list structure.

List items (<li>) are contained within <ul>, <ol> or <menu> parent elements

Screen readers require list items (<li>) to be contained within a parent <ul>, <ol> or <menu> to be announced properly. Learn more about proper list structure.

Select elements have associated label elements.

Form elements without effective labels can create frustrating experiences for screen reader users. Learn more about the select element.

No element has a [tabindex] value greater than 0

Touch targets have sufficient size and spacing.

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Heading elements appear in a sequentially-descending order

Uses ARIA roles only on compatible elements

Many HTML elements can only be assigned certain ARIA roles. Using ARIA roles where they are not allowed can interfere with the accessibility of the web page. Learn more about ARIA roles.

Deprecated ARIA roles were not used

Deprecated ARIA roles may not be processed correctly by assistive technology. Learn more about deprecated ARIA roles.

Image elements do not have [alt] attributes that are redundant text.

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[accesskey] values are unique

Access keys let users quickly focus a part of the page. For proper navigation, each access key must be unique. Learn more about access keys.

button, link, and menuitem elements have accessible names

ARIA input fields have accessible names

When an input field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about input field labels.

ARIA meter elements have accessible names

When a meter element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to name meter elements.

ARIA progressbar elements have accessible names

Elements with an ARIA [role] that require children to contain a specific [role] have all required children.

Some ARIA parent roles must contain specific child roles to perform their intended accessibility functions. Learn more about roles and required children elements.

[role]s are contained by their required parent element

Some ARIA child roles must be contained by specific parent roles to properly perform their intended accessibility functions. Learn more about ARIA roles and required parent element.

Elements with the role=text attribute do not have focusable descendents.

ARIA toggle fields have accessible names

When a toggle field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about toggle fields.

ARIA treeitem elements have accessible names

The page contains a heading, skip link, or landmark region

Adding ways to bypass repetitive content lets keyboard users navigate the page more efficiently. Learn more about bypass blocks.

<dl>'s contain only properly-ordered <dt> and <dd> groups, <script>, <template> or <div> elements.

When definition lists are not properly marked up, screen readers may produce confusing or inaccurate output. Learn how to structure definition lists correctly.

Definition list items are wrapped in <dl> elements

Definition list items (<dt> and <dd>) must be wrapped in a parent <dl> element to ensure that screen readers can properly announce them. Learn how to structure definition lists correctly.

ARIA IDs are unique

The value of an ARIA ID must be unique to prevent other instances from being overlooked by assistive technologies. Learn how to fix duplicate ARIA IDs.

No form fields have multiple labels

Form fields with multiple labels can be confusingly announced by assistive technologies like screen readers which use either the first, the last, or all of the labels. Learn how to use form labels.

<frame> or <iframe> elements have a title

Screen reader users rely on frame titles to describe the contents of frames. Learn more about frame titles.

<html> element has an [xml:lang] attribute with the same base language as the [lang] attribute.

If the webpage does not specify a consistent language, then the screen reader might not announce the page's text correctly. Learn more about the lang attribute.

Input buttons have discernible text.

Adding discernable and accessible text to input buttons may help screen reader users understand the purpose of the input button. Learn more about input buttons.

<input type="image"> elements have [alt] text

When an image is being used as an <input> button, providing alternative text can help screen reader users understand the purpose of the button. Learn about input image alt text.

The document does not use <meta http-equiv="refresh">

<object> elements have alternate text

Screen readers cannot translate non-text content. Adding alternate text to <object> elements helps screen readers convey meaning to users. Learn more about alt text for object elements.

Tables have different content in the summary attribute and <caption>.

Cells in a <table> element that use the [headers] attribute refer to table cells within the same table.

<th> elements and elements with [role="columnheader"/"rowheader"] have data cells they describe.

[lang] attributes have a valid value

Specifying a valid BCP 47 language on elements helps ensure that text is pronounced correctly by a screen reader. Learn how to use the lang attribute.

<video> elements contain a <track> element with [kind="captions"]

When a video provides a caption it is easier for deaf and hearing impaired users to access its information. Learn more about video captions.

Best Practices

Uses deprecated APIs 1 warning found

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Deprecation / Warning	Source
sainsburys.co.uk 1st party
Unload event listeners are deprecated and will be removed.	https://www.sainsburys.co.uk:302:29511

Detected JavaScript libraries

All front-end JavaScript libraries detected on the page. Learn more about this JavaScript library detection diagnostic audit.

Name	Version
jQuery	3.5.1
React
Gatsby

Missing source maps for large first-party JavaScript

URL	Map URL
sainsburys.co.uk 1st party
/assets/app-174….js (www.sainsburys.co.uk)
Large JavaScript file is missing a source map

Ensure CSP is effective against XSS attacks

A strong Content Security Policy (CSP) significantly reduces the risk of cross-site scripting (XSS) attacks. Learn how to use a CSP to prevent XSS

Description	Directive	Severity
`script-src` directive is missing. This can allow the execution of unsafe scripts.	script-src	High
Missing `object-src` allows the injection of plugins that execute unsafe scripts. Consider setting `object-src` to `'none'` if you can.	object-src	High

Use a strong HSTS policy

Description	Directive	Severity
`max-age` is too low	max-age	High
No `preload` directive found	preload	Medium

Ensure proper origin isolation with COOP

The Cross-Origin-Opener-Policy (COOP) can be used to isolate the top-level window from other documents such as pop-ups. Learn more about deploying the COOP header.

Description	Directive	Severity
No COOP header found		High

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Uses HTTPS

Avoids third-party cookies

Chrome is moving towards a new experience that allows users to choose to browse without third-party cookies. Learn more about third-party cookies.

Allows users to paste into input fields

Preventing input pasting is a bad practice for the UX, and weakens security by blocking password managers.Learn more about user-friendly input fields.

Avoids requesting the geolocation permission on page load

Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to a user action instead. Learn more about the geolocation permission.

Avoids requesting the notification permission on page load

Displays images with correct aspect ratio

Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

Serves images with appropriate resolution

Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.

Has a <meta name="viewport"> tag with width or initial-scale

A <meta name="viewport"> not only optimizes your app for mobile screen sizes, but also prevents a 300 millisecond delay to user input. Learn more about using the viewport meta tag.

Page has the HTML doctype

Specifying a doctype prevents the browser from switching to quirks-mode. Learn more about the doctype declaration.

Properly defines charset

No browser errors logged to the console

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

No issues in the Issues panel in Chrome Devtools

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Redirects HTTP traffic to HTTPS

Make sure that you redirect all HTTP traffic to HTTPS in order to enable secure web features for all your users. Learn more.

Mitigate clickjacking with XFO or CSP

Document uses legible font sizes

100

SEO

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Structured data is valid

Run the Structured Data Testing Tool and the Structured Data Linter to validate structured data. Learn more about Structured Data.

Run these additional validators on your site to check additional SEO best practices.

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Page isn’t blocked from indexing

Search engines are unable to include your pages in search results if they don't have permission to crawl them. Learn more about crawler directives.

Document has a <title> element

The title gives screen reader users an overview of the page, and search engine users rely on it heavily to determine if a page is relevant to their search. Learn more about document titles.

Document has a meta description

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

Page has successful HTTP status code

Pages with unsuccessful HTTP status codes may not be indexed properly. Learn more about HTTP status codes.

Links have descriptive text

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Links are crawlable

robots.txt is valid

If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. Learn more about robots.txt.

Image elements have [alt] attributes

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the alt attribute.

Document has a valid hreflang

hreflang links tell search engines what version of a page they should list in search results for a given language or region. Learn more about hreflang.

Document has a valid rel=canonical

Canonical links suggest which URL to show in search results. Learn more about canonical links.