Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
assets.adobedtm.com/launch-ENfdadf1bb09d848de85923e05be32e7d1.min.js	3600.0 s	134.2 KiB
js-cdn.dynatrace.com/jstag/17f0bd28e42/bf88365yqv/95b067d34295602_complete.js	3600.0 s	85.1 KiB
cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js	86400.0 s	114.6 KiB
/logos/a0327856-31fc-4f51-b6d3-1c9e883e1ecf/6be977a3-7778...	86400.0 s	77.9 KiB
www.bt.com/home/_next/static/media/Non-Dottee-Regular.32dec766.woff2	0.0 ms	28.1 KiB
www.bt.com/home/_next/static/media/BTCurve_W_Bd.50264748.woff2	0.0 ms	20.7 KiB
www.bt.com/home/_next/static/media/BTCurve_W_Headline.dfb8c48d.woff2	0.0 ms	20.6 KiB
www.bt.com/home/_next/static/media/BTCurve_W_Rg.d1585de4.woff2	0.0 ms	20.1 KiB
www.bt.com/home/_next/static/media/Dottee-Condensed-Regular.dfe2f558.woff2	0.0 ms	16.3 KiB
/consent/93aec36f-64c3-487b-897d-5e8f88cbe7b9/otSDKStub.js	86400.0 s	8.1 KiB
/logos/a0327856-31fc-4f51-b6d3-1c9e883e1ecf/6be977a3-7778...	86400.0 s	4.8 KiB
/468fd5a0b220/5e2a7b1f96d2/9b43926a1d72/RC31e920520b184dd...	3600.0 s	2.3 KiB
cdn-ukwest.onetrust.com/logos/static/powered_by_logo.svg	86400.0 s	2.6 KiB
/468fd5a0b220/5e2a7b1f96d2/9b43926a1d72/RCa03154b2b77741a...	3600.0 s	892 B
/468fd5a0b220/5e2a7b1f96d2/9b43926a1d72/RCfe97f628783b436...	3600.0 s	883 B
/468fd5a0b220/5e2a7b1f96d2/9b43926a1d72/RC006b154332e540a...	3600.0 s	610 B
/468fd5a0b220/5e2a7b1f96d2/9b43926a1d72/RCb3ca17af02e145b...	3600.0 s	495 B
/468fd5a0b220/5e2a7b1f96d2/9b43926a1d72/RC1318737ea17348d...	3600.0 s	487 B
www.gstatic.com/recaptcha/api2/logo_48.png	604800.0 s	2.3 KiB

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]

items: [map[node:map[type:text value:Total] score:0.13755] map[node:map[boundingRect:map[bottom:7288 height:7228 left:0 right:412 top:60 width:412] lhId:page-24-MAIN nodeLabel:Don’t have BT Broadband yet? Find your available deals Upgrade your home with B… path:1,HTML,1,BODY,0,DIV,0,DIV,1,MAIN selector:body > div#__next > div.lc > main#maincontent snippet:<main id="maincontent" role="main"> type:node] score:0.072904 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:4182 height:255 left:16 right:396 top:3926 width:380] lhId:page-3-IMG nodeLabel:div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD path:1,HTML,1,BODY,0,DIV,0,DIV,1,MAIN,1,DIV,7,SECTION,1,DIV,0,IMG selector:div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD snippet:<img alt="" loading="lazy" width="600" height="400" decoding="async" data-nimg="1" class="sectionUpliftFour_sectionImage__A_9lD" src="https://img01.products.bt.co.uk/content/dam/bt/storefront/bt-home/newcust-…" style="color: transparent;"> type:node]]] type:subitems]] map[node:map[boundingRect:map[bottom:1062 height:365 left:10 right:402 top:697 width:391] lhId:page-23-DIV nodeLabel:Trusted, reliable broadband Exclusive deals just for you Already a BT customer… path:1,HTML,1,BODY,0,DIV,0,DIV,1,MAIN,1,DIV,1,SECTION,2,DIV,0,DIV selector:div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_leftContent__lMQTI snippet:<div class="sectionUpliftOne_leftContent__lMQTI"> type:node] score:0.064473 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:4182 height:255 left:16 right:396 top:3926 width:380] lhId:page-3-IMG nodeLabel:div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD path:1,HTML,1,BODY,0,DIV,0,DIV,1,MAIN,1,DIV,7,SECTION,1,DIV,0,IMG selector:div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD snippet:<img alt="" loading="lazy" width="600" height="400" decoding="async" data-nimg="1" class="sectionUpliftFour_sectionImage__A_9lD" src="https://img01.products.bt.co.uk/content/dam/bt/storefront/bt-home/newcust-…" style="color: transparent;"> type:node]] map[cause:Web font extra:map[type:url value:https://www.bt.com/home/_next/static/media/Dottee-Condensed-Regular.dfe2f558.woff2]] map[cause:Web font extra:map[type:url value:https://www.bt.com/home/_next/static/media/BTCurve_W_Bd.50264748.woff2]]] type:subitems]] map[node:map[boundingRect:map[bottom:60 height:60 left:317 right:397 top:0 width:80] lhId:page-25-DIV nodeLabel:More path:1,HTML,1,BODY,0,DIV,0,DIV,0,HEADER,0,DIV,1,DIV,1,NAV,0,DIV,1,DIV selector:div.globalnavigation > nav.container-fluid > div.global-nav-container > div.global-nav-right snippet:<div class="global-nav-right"> type:node] score:0.000173 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:4182 height:255 left:16 right:396 top:3926 width:380] lhId:page-3-IMG nodeLabel:div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD path:1,HTML,1,BODY,0,DIV,0,DIV,1,MAIN,1,DIV,7,SECTION,1,DIV,0,IMG selector:div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD snippet:<img alt="" loading="lazy" width="600" height="400" decoding="async" data-nimg="1" class="sectionUpliftFour_sectionImage__A_9lD" src="https://img01.products.bt.co.uk/content/dam/bt/storefront/bt-home/newcust-…" style="color: transparent;"> type:node]]] type:subitems]]]

items: [map[node:map[type:text value:Total] score:0.000249] map[node:map[boundingRect:map[bottom:59 height:59 left:173 right:212 top:0 width:39] lhId:page-26-LI nodeLabel:TV path:1,HTML,1,BODY,0,DIV,0,DIV,0,HEADER,0,DIV,1,DIV,1,NAV,0,DIV,0,DIV,1,UL,1,LI selector:div.global-nav-container > div.global-nav-left > ul.top-level-menu > li.top-level-item snippet:<li class="top-level-item inline-block" style=""> type:node] score:0.000249]]

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Est Savings
www.bt.com/exp/home/_next/static/media/BTCurve_W_Rg.d1585de4.woff2	340 ms
fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2	35 ms
www.bt.com/etc.clientlibs/global/clientlibs/resources/fonts/bt-icons.woff	10 ms

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:24.585 source:map[column:139911 line:1 type:source-location url:https://www.bt.com/home/_next/static/chunks/framework-050c1f32293f7182.js urlProvider:network]]]

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:2.193 source:map[column:6456 line:0 type:source-location url:https://www.bt.com/home/_next/static/chunks/pages/_app-c46a38d10daabda4.js urlProvider:network]] map[reflowTime:29.338 source:map[type:text value:[unattributed]]] map[reflowTime:8.143 source:map[column:12932 line:0 type:source-location url:https://www.bt.com/home/_next/static/chunks/3-438b0bb789ecd2ca.js urlProvider:network]] map[reflowTime:11.838 source:map[column:56473 line:0 type:source-location url:https://www.bt.com/home/_next/static/chunks/3-438b0bb789ecd2ca.js urlProvider:network]] map[reflowTime:1.152 source:map[column:33079 line:0 type:source-location url:https://www.bt.com/home/_next/static/chunks/3-438b0bb789ecd2ca.js urlProvider:network]] map[reflowTime:2.88 source:map[column:95812 line:0 type:source-location url:https://www.bt.com/home/_next/static/chunks/3-438b0bb789ecd2ca.js urlProvider:network]] map[reflowTime:0.572 source:map[column:109587 line:0 type:source-location url:https://www.bt.com/home/_next/static/chunks/3-438b0bb789ecd2ca.js urlProvider:network]] map[reflowTime:0.471 source:map[column:110303 line:0 type:source-location url:https://www.bt.com/home/_next/static/chunks/3-438b0bb789ecd2ca.js urlProvider:network]] map[reflowTime:9.241 source:map[column:269989 line:6 type:source-location url:https://cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:0.155 source:map[column:270333 line:6 type:source-location url:https://cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:0.336 source:map[column:319197 line:6 type:source-location url:https://cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:0.311 source:map[column:332 line:412 type:source-location url:https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js urlProvider:network]] map[reflowTime:0.437 source:map[column:30 line:6590 type:source-location url: urlProvider:network]] map[reflowTime:0.136 source:map[column:51 line:6598 type:source-location url: urlProvider:network]] map[reflowTime:0.108 source:map[column:45 line:6609 type:source-location url: urlProvider:network]] map[reflowTime:2.284 source:map[column:53 line:6737 type:source-location url: urlProvider:network]] map[reflowTime:6.895 source:map[column:17 line:6737 type:source-location url: urlProvider:network]] map[reflowTime:0.189 source:map[column:50 line:6699 type:source-location url: urlProvider:network]] map[reflowTime:2.514 source:map[column:13 line:7207 type:source-location url: urlProvider:network]] map[reflowTime:0.206 source:map[column:250 line:142 type:source-location url:https://js-cdn.dynatrace.com/jstag/17f0bd28e42/bf88365yqv/95b067d34295602_complete.js urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
div.existing-customer-uplift_wrapper__EhiFs > section.sectionBannerLeftText_sectionBanner__5vkcE > picture > img.lazyload `div.existing-customer-uplift_wrapper__EhiFs > section.sectionBannerLeftText_sectionBanner__5vkcE > picture > img.lazyload`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	135.5 KiB	84.0 KiB
Company Logo `div#onetrust-group-container > div#onetrust-policy > div.banner-header > img.ot-bnr-logo`	/logos/a0327856-31fc-4f51-b6d3-1c9e883e1ecf/6be977a3-7778...	77.7 KiB	77.5 KiB
div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA `div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	75.2 KiB	68.8 KiB
div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD `div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftFour_rightBlock__qx2ZT > img.sectionUpliftFour_sectionImage__A_9lD`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	95.2 KiB	54.9 KiB
div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA `div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	55.1 KiB	44.3 KiB
div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA `div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	48.7 KiB	42.0 KiB
div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA `div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	36.1 KiB	30.6 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	36.0 KiB	23.8 KiB
section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_rightImage__rDMen > img.sectionUpliftOne_imageMobile__M_JMg `section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_rightImage__rDMen > img.sectionUpliftOne_imageMobile__M_JMg`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	55.3 KiB	23.7 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	32.8 KiB	20.5 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	31.7 KiB	19.4 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	31.2 KiB	18.9 KiB
div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA `div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	21.0 KiB	17.2 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	29.0 KiB	16.7 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	27.5 KiB	15.2 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	25.7 KiB	13.4 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	24.4 KiB	12.1 KiB
section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_leftImage__sQg9_ > img.sectionUpliftOne_imageMobile__M_JMg `section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_leftImage__sQg9_ > img.sectionUpliftOne_imageMobile__M_JMg`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	34.1 KiB	10.9 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	19.8 KiB	7.5 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	19.6 KiB	7.3 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	19.4 KiB	7.2 KiB
div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA `div.sectionUpliftTwo_card__xEuYe > div.sectionUpliftTwo_bottomWrapper__oEdvd > div.sectionUpliftTwo_imageWrapper__0ujZ4 > img.sectionUpliftTwo_addonImage__OHlkA`	/content/dam/bt/storefront/bt-home/extcust-uplift/images/...	11.7 KiB	5.4 KiB
div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr `div.rfm-marquee > div.rfm-child > div.sectionUpliftThree_card___KMjD > img.sectionUpliftThree_marqueeImage__hg_dr`	/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	17.3 KiB	5.1 KiB

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-8-IMG

nodeLabel: section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_rightImage__rDMen > img.sectionUpliftOne_imageMobile__M_JMg

path: 1,HTML,1,BODY,0,DIV,0,DIV,1,MAIN,1,DIV,1,SECTION,2,DIV,1,DIV,0,IMG

selector: section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_rightImage__rDMen > img.sectionUpliftOne_imageMobile__M_JMg

snippet: <img alt="" loading="lazy" width="600" height="400" decoding="async" data-nimg="1" class="sectionUpliftOne_imageMobile__M_JMg" src="https://img01.products.bt.co.uk/content/dam/bt/storefront/bt-home/extcust-…" style="color: transparent;">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 1.5 s

URL	Time Spent
bt.com/	751 ms
www.bt.com/	758 ms
www.bt.com/	0.0 ms

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 CLS

Why this matters

Performance issues directly impact user engagement and conversion rates.

Element	Layout shift score
Don’t have BT Broadband yet? Find your available deals Upgrade your home with B… `body > div#__next > div.lc > main#maincontent`	0.073
Trusted, reliable broadband Exclusive deals just for you Already a BT customer… `div.existing-customer-uplift_wrapper__EhiFs > section.bt-container > div.sectionUpliftOne_contentWrapper__EMPgt > div.sectionUpliftOne_leftContent__lMQTI`	0.064
TV `div.global-nav-container > div.global-nav-left > ul.top-level-menu > li.top-level-item`	0.000
More `div.globalnavigation > nav.container-fluid > div.global-nav-container > div.global-nav-right`	0.000

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 47.4 KiB

URL	Transfer Size	Est Savings
www.bt.com/home/_next/static/css/d7c01f3734e5ed92.css	32.3 KiB	29.7 KiB
	20.8 KiB	17.7 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 600 ms 436.3 KiB

URL	Transfer Size	Est Savings
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js	361.8 KiB	177.0 KiB
www.googletagmanager.com/gtag/js?id=G-19536D3EL2	176.2 KiB	77.0 KiB
assets.adobedtm.com/launch-ENfdadf1bb09d848de85923e05be32e7d1.min.js	133.9 KiB	65.4 KiB
cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js	114.3 KiB	60.8 KiB
js-cdn.dynatrace.com/jstag/17f0bd28e42/bf88365yqv/95b067d34295602_complete.js	84.6 KiB	33.6 KiB
www.bt.com/home/_next/static/chunks/framework-050c1f32293f7182.js	59.1 KiB	22.5 KiB

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Total CPU Time	Script Evaluation	Script Parse
www.bt.com/	859 ms	104 ms	1.1 ms
www.bt.com/home/_next/static/chunks/pages/_app-c46a38d10daabda4.js	745 ms	508 ms	124 ms
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js	666 ms	578 ms	69 ms
www.bt.com/home/_next/static/chunks/framework-050c1f32293f7182.js	628 ms	450 ms	14 ms
Unattributable	580 ms	19 ms	0.0 ms
js-cdn.dynatrace.com/jstag/17f0bd28e42/bf88365yqv/95b067d34295602_complete.js	442 ms	317 ms	32 ms
assets.adobedtm.com/launch-ENfdadf1bb09d848de85923e05be32e7d1.min.js	238 ms	178 ms	51 ms
www.googletagmanager.com/gtag/js?id=G-19536D3EL2	224 ms	180 ms	42 ms
www.bt.com/home/_next/static/chunks/main-703d0df2c17dec2d.js	80 ms	71 ms	9.0 ms
/consent/93aec36f-64c3-487b-897d-5e8f88cbe7b9/otSDKStub.js	77 ms	72 ms	1.7 ms
cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js	69 ms	33 ms	35 ms
www.bt.com/home/_next/static/chunks/pages/index-bdd4a1f377a76969.js	66 ms	62 ms	2.8 ms
/_Incapsula_Resource?SWJIYLWA=719d34d31c8e3a6e6fffd425f7e...	53 ms	44 ms	5.7 ms
www.bt.com/home/_next/static/chunks/3-438b0bb789ecd2ca.js	51 ms	16 ms	12 ms

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 work

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Script Evaluation	2.8 s
Other	894 ms
Style & Layout	553 ms
Script Parsing & Compilation	423 ms
Rendering	202 ms
Parse HTML & CSS	87 ms
Garbage Collection	65 ms

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js	362.4 KiB
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js	361.9 KiB
www.bt.com/etc.clientlibs/global/clientlibs.min.js	258.2 KiB
www.googletagmanager.com/gtag/js?id=G-19536D3EL2	176.5 KiB
/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	135.9 KiB
assets.adobedtm.com/launch-ENfdadf1bb09d848de85923e05be32e7d1.min.js	134.2 KiB
cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js	114.6 KiB
/content/dam/bt/storefront/bt-home/newcust-uplift/images/...	95.6 KiB
js-cdn.dynatrace.com/jstag/17f0bd28e42/bf88365yqv/95b067d34295602_complete.js	85.1 KiB
/logos/a0327856-31fc-4f51-b6d3-1c9e883e1ecf/6be977a3-7778...	77.9 KiB

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL
BT Logo `div.global-nav-container > div.global-nav-left > a.global-nav-logo-link > img.global-nav-logo`	www.bt.com/content/dam/bt/global/logos/BTlogo_RGB_White.svg

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

●Optimize DOM size

●LCP breakdown

●Modern HTTP

●Render blocking requests

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●User Timing marks and measures 4 user timings

●Avoid long main-thread tasks 20 long tasks found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 30 ms

●Server Backend Latencies 40 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 80 ms

○INP breakdown

○Avoid non-composited animations

100

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.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
BT Broadband Reliable. Fast BT’s trusted network with brilliant services View … `nav.swiper > div#swiper-wrapper-84aaedcef74fcdf5 > div.swiper-slide > a`
iPhone offer Latest. iPhone 17 Pro New exclusive offer - BT Broadband customers… `nav.swiper > div#swiper-wrapper-84aaedcef74fcdf5 > div.swiper-slide > a`
Cookie Policy `div#onetrust-group-container > div#onetrust-policy > div#onetrust-policy-text > a.ot-cookie-policy-link`

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

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

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

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

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

●`[role]` values are valid

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●Buttons have an accessible name

●Image elements have `[alt]` attributes

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

●`button`, `link`, and `menuitem` elements have accessible names

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

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

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

●Elements use only permitted ARIA attributes

●Background and foreground colors have a sufficient contrast ratio

●Document has a `<title>` element

●`<frame>` or `<iframe>` elements have a title

●`<html>` element has a `[lang]` attribute

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

●Links are distinguishable without relying on color.

●Links have a discernible name

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

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

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

●Skip links are focusable.

●Document has a main landmark.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

○`[accesskey]` values are unique

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

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

○`[role]`s are contained by their required parent element

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

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

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

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

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

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

○Input buttons have discernible text.

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

○Form elements have associated labels

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

○`<object>` elements have alternate text

○Select elements have associated label elements.

○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

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

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

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

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

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

Best Practices

General

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / Warning	Source
Specifying overflow: visible on img, video and canvas tags may cause them to produce visual content outside of the element bounds. See https://github.com/WICG/shared-element-transitions/blob/main/debugging_overflow_on_images.md.	cdn-ukwest.onetrust.com/scripttemplates/202501.2.0/otBannerSdk.js line 6, col 269989

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source	Description
www.bt.com/exp/home/_next/static/media/BTCurve_W_Rg.d1585de4.woff2	`Failed to load resource: the server responded with a status of 403 ()`

●Uses HTTPS

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Mitigate clickjacking with XFO or CSP

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.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links have descriptive text

●Links are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`