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Lighthouse Mobile

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

Audit breakdown by category with detailed findings.

23

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.

RequestCache TTLTransfer Size
www.delta.com/content/dam/delta-tnt/homepage/card-cd/brycecanyon-ut-slc-945.webp0.0 ms151.2 KiB
www.delta.com/content/dam/delta-tnt/homepage/btf/wf-3383622-01-1050x600.webp0.0 ms140.4 KiB
/content/dam/delta-tnt/homepage/hero/2025/Retail/current-...0.0 ms128.6 KiB
/content/dam/delta-tnt/homepage/hero/2025/Retail/current-...0.0 ms125.0 KiB
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB21600.0 s172.8 KiB
/content/dam/delta-com/products/delta-experiences/main-ca...0.0 ms91.6 KiB
/content/dam/delta-tnt/homepage/card-cd/premium-cabin-dea...0.0 ms73.0 KiB
/content/dam/delta-com/products/delta-experiences/delta-p...0.0 ms60.3 KiB
www.delta.com/content/dam/delta-tnt/homepage/btf/wf-3175001-02-1050x600.webp0.0 ms56.5 KiB
cdn.cookielaw.org/scripttemplates/202503.1.0/otBannerSdk.js86400.0 s115.9 KiB
www.delta.com/content/dam/delta-com/products/map/fda-homepage-700x425.webp0.0 ms39.2 KiB
www.delta.com/ruxitagentjs_ICA27NVfghjqrx_10285240307101407.js86400.0 s75.3 KiB
www.delta.com/content/dam/delta-tnt/homepage/covid/icon-flight-changes-1000.webp0.0 ms9.1 KiB
cdn.cookielaw.org/scripttemplates/otSDKStub.js86400.0 s9.1 KiB
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RC955d0ae6fa194fa...3600.0 s4.3 KiB
/logos/6b6d972e-480d-4bb2-96d3-4bf62b3d9551/0191fd5a-9aa4...86400.0 s3.6 KiB
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RC6d20ec2c5bbb40d...3600.0 s1.5 KiB
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RC5618ada8bb5b47d...3600.0 s1.4 KiB
cdn.cookielaw.org/logos/static/powered_by_logo.svg86400.0 s2.1 KiB
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RCe7c3c47950ce471...3600.0 s1.0 KiB
/usage.gif?token=40c5d1df6a8049dfa571d3e4324bef72&correla...0.0 ms273 B
/usage.gif?token=40c5d1df6a8049dfa571d3e4324bef72&correla...0.0 ms273 B
cdn.cookielaw.org/logos/static/ot_close.svg86400.0 s643 B
www.delta.com/homepage/26.3.8/mach-core/browser/main.js10635.0 s0 B
www.delta.com/homepage/26.3.8/mach-core/browser/styles.css86400.0 s0 B
/NxvV2/ISv/V5F2/Si/veeSUD/wb7hbLaQ/K0ciPAE/UHQfJX/dcDxdt?...21600.0 s0 B
assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js3600.0 s0 B
www.delta.com/resources/df032bb95163120c0d0265eb98f27f913a30d77a1d98e600.0 s0 B
s.go-mpulse.net/boomerang/PWV8J-R2M7Y-67AAN-EA9TD-6DRAX604800.0 s0 B
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/wb/d1V3OwE/UmB7Xj/cGAGcp86400.0 s0 B
p11.techlab-cdn.com/e/65226_747628124.js600.0 s0 B
p11.techlab-cdn.com/e/65319_1825172608.js600.0 s0 B
www.delta.com/homepage/26.3.8/mach-core/browser/polyfills.js10628.0 s0 B
www.delta.com/content/dam/delta-applications/login/assets/tracker-3.10.1.js604800.0 s0 B
cdn.cookielaw.org/scripttemplates/otSDKStub.js86400.0 s0 B
p11.techlab-cdn.com/e/65257_1825202461.js600.0 s0 B
p11.techlab-cdn.com/e/64885_1825202492.js600.0 s0 B
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/wb/d1V3OwE/HyYAC1/0AVHVY86400.0 s0 B
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RC9c4892907897447...3600.0 s0 B
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RC286d4830056d424...3600.0 s0 B

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:0.10698000000000002] map[node:map[boundingRect:map[bottom:3206 height:2880 left:0 right:412 top:326 width:412] lhId:page-3-DIV nodeLabel:Book Your Next Trip Explore our current flight deals and plan your next adventu… path:1,HTML,1,BODY,2,IDP-ROOT,1,IDP-CONTENT-BODY,2,DIV selector:body > idp-root > idp-content-body > div#content-body-mach-core snippet:<div id="content-body-mach-core" role="main" data-acdl-page="homepage"> type:node] score:0.037146] map[node:map[boundingRect:map[bottom:807 height:281 left:0 right:412 top:526 width:412] lhId:page-5-DIV nodeLabel:Delta and our third party partners access and store data on your device as nece… path:1,HTML,1,BODY,17,DIV,1,DIV selector:body > div#onetrust-consent-sdk > div#onetrust-banner-sdk snippet:<div id="onetrust-banner-sdk" class="otFloatingRounded ot-bottom-left ot-wo-title" tabindex="0" role="region" aria-label="Preference banner" style="bottom: 1rem;"> type:node] score:0.013811] map[node:map[boundingRect:map[bottom:807 height:281 left:0 right:412 top:526 width:412] lhId:page-5-DIV nodeLabel:Delta and our third party partners access and store data on your device as nece… path:1,HTML,1,BODY,17,DIV,1,DIV selector:body > div#onetrust-consent-sdk > div#onetrust-banner-sdk snippet:<div id="onetrust-banner-sdk" class="otFloatingRounded ot-bottom-left ot-wo-title" tabindex="0" role="region" aria-label="Preference banner" style="bottom: 1rem;"> type:node] score:0.006738] map[node:map[boundingRect:map[bottom:1240 height:392 left:0 right:412 top:848 width:412] lhId:page-1-DIV nodeLabel:How Can I Change/Cancel My Flight? We understand that your plans may change. It… path:1,HTML,1,BODY,2,IDP-ROOT,1,IDP-CONTENT-BODY,2,DIV,4,DIV,2,DIV selector:idp-content-body > div#content-body-mach-core > div.cmp-container > div.cards snippet:<div class="cards"> type:node] score:0.004253] map[node:map[boundingRect:map[bottom:807 height:281 left:0 right:412 top:526 width:412] lhId:page-5-DIV nodeLabel:Delta and our third party partners access and store data on your device as nece… path:1,HTML,1,BODY,17,DIV,1,DIV selector:body > div#onetrust-consent-sdk > div#onetrust-banner-sdk snippet:<div id="onetrust-banner-sdk" class="otFloatingRounded ot-bottom-left ot-wo-title" tabindex="0" role="region" aria-label="Preference banner" style="bottom: 1rem;"> type:node] score:0.003588]]

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:26.972 source:map[column:15836 line:1 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/polyfills.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:1.842 source:map[column:858108 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:3.444 source:map[column:2.710484e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:3.14 source:map[column:2.71056e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:1.084 source:map[column:2.863709e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:10.178 source:map[column:2.864655e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:2.442 source:map[column:3.011514e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:4.842 source:map[column:2.863914e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:1.114 source:map[column:2.868853e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:1.007 source:map[column:2.869398e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:0.648 source:map[column:2.870304e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]] map[reflowTime:0.65 source:map[column:2.866235e+06 line:0 type:source-location url:https://www.delta.com/homepage/26.3.8/mach-core/browser/main.js urlProvider:network]]]

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]
items: [map[duration:277.328 label:Time to first byte subpart:timeToFirstByte] map[duration:2033.591 label:Resource load delay subpart:resourceLoadDelay] map[duration:198.57 label:Resource load duration subpart:resourceLoadDuration] map[duration:146.011 label:Element render delay subpart:elementRenderDelay]]
lhId: page-0-IMG
nodeLabel: Image of seaside town
path: 1,HTML,1,BODY,2,IDP-ROOT,1,IDP-CONTENT-BODY,2,DIV,4,DIV,0,DIV,1,DIV,2,IMG
selector: div.cmp-container > div.hero > div.bg-surface-navigation > img.tablet:hidden
snippet: <img alt="Image of seaside town " class="tablet:hidden block h-full w-full object-cover" src="/content/dam/delta-tnt/homepage/hero/2025/Retail/current-flight-deals/wf-3…" fetchpriority="high" width="800" height="670">

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-0-IMG
nodeLabel: Image of seaside town
path: 1,HTML,1,BODY,2,IDP-ROOT,1,IDP-CONTENT-BODY,2,DIV,4,DIV,0,DIV,1,DIV,2,IMG
selector: div.cmp-container > div.hero > div.bg-surface-navigation > img.tablet:hidden
snippet: <img alt="Image of seaside town " class="tablet:hidden block h-full w-full object-cover" src="/content/dam/delta-tnt/homepage/hero/2025/Retail/current-flight-deals/wf-3…" fetchpriority="high" width="800" height="670">

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.

More than 4 preconnect connections were found. These should be used sparingly and only to the most important origins.
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

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.

URLResource SizeEst Savings
Ready For Adventure? section.w-full > div.image-card > div.card-image-ratio > img.card-image-content
www.delta.com/content/dam/delta-tnt/homepage/card-cd/brycecanyon-ut-slc-945.webp150.6 KiB105.4 KiB
Discover Travel Products section.w-full > div.image-card > div.card-image-ratio > img.card-image-content
www.delta.com/content/dam/delta-tnt/homepage/btf/wf-3383622-01-1050x600.webp139.8 KiB99.1 KiB
/content/dam/delta-com/products/delta-experiences/main-ca...91.0 KiB47.4 KiB
/content/dam/delta-com/products/delta-experiences/delta-p...59.8 KiB35.7 KiB
Image of the FlyDelta App div.w-full > div.image-card > div.card-image-ratio > img.card-image-content
www.delta.com/content/dam/delta-tnt/homepage/btf/wf-3175001-02-1050x600.webp56.0 KiB33.3 KiB
Elevate Your Flight Experience section.w-full > div.image-card > div.card-image-ratio > img.card-image-content
/content/dam/delta-tnt/homepage/card-cd/premium-cabin-dea...72.5 KiB32.5 KiB
How Can I Change/Cancel My Flight? div.w-full > div.image-card > div.card-image-ratio > img.card-image-content
www.delta.com/content/dam/delta-tnt/homepage/covid/icon-flight-changes-1000.webp8.7 KiB4.6 KiB

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer SizeDuration
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB172.8 KiB1.6 s
www.delta.com/content/dam/delta-applications/login/assets/tracker-3.10.1.js0 B
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/wb/d1V3OwE/HyYAC1/0AVHVY0 B
www.delta.com/homepage/26.3.8/mach-core/browser/styles.css0 B627 ms

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

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.

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: 12.3 s
URLTime Spent
www.delta.com/12.3 s
www.delta.com/eu/en0.0 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.

ElementLayout shift score
Book Your Next Trip Explore our current flight deals and plan your next adventu… body > idp-root > idp-content-body > div#content-body-mach-core
0.037
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.014
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.007
How Can I Change/Cancel My Flight? We understand that your plans may change. It… idp-content-body > div#content-body-mach-core > div.cmp-container > div.cards
0.004
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.004
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.002
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.002
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.002
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001
Delta and our third party partners access and store data on your device as nece… body > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001

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

Diagnostics

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: 5.7 s 1.3 MiB
URLTransfer SizeEst Savings
www.delta.com/homepage/26.3.8/mach-core/browser/main.js660.9 KiB355.2 KiB
www.delta.com/homepage/26.3.8/mach-core/browser/main.js660.9 KiB347.8 KiB
/NxvV2/ISv/V5F2/Si/veeSUD/wb7hbLaQ/K0ciPAE/UHQfJX/dcDxdt?...159.4 KiB81.4 KiB
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB171.5 KiB67.1 KiB
cdn.cookielaw.org/scripttemplates/202503.1.0/otBannerSdk.js115.8 KiB61.5 KiB
tms.delta.com/delta/dl_anderson/Bootstrap.js96.0 KiB51.4 KiB
assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js99.8 KiB48.7 KiB
tms.delta.com/delta/dl_anderson/Bootstrap.js96.0 KiB45.1 KiB
assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js99.8 KiB37.2 KiB
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB171.5 KiB35.8 KiB
/NxvV2/ISv/V5F2/Si/veeSUD/wb7hbLaQ/K0ciPAE/UHQfJX/dcDxdt?...159.4 KiB33.2 KiB
s.go-mpulse.net/boomerang/PWV8J-R2M7Y-67AAN-EA9TD-6DRAX48.6 KiB32.6 KiB
s.go-mpulse.net/boomerang/PWV8J-R2M7Y-67AAN-EA9TD-6DRAX48.6 KiB29.6 KiB
www.delta.com/resources/df032bb95163120c0d0265eb98f27f913a30d77a1d98e61.7 KiB23.4 KiB
www.delta.com/resources/df032bb95163120c0d0265eb98f27f913a30d77a1d98e61.7 KiB21.5 KiB
/delta/dl_anderson/code/a7f0e2c2a7413c6659c51a8ec43b3e6a....29.8 KiB21.4 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.

URLTotal CPU TimeScript EvaluationScript Parse
www.delta.com/resources/df032bb95163120c0d0265eb98f27f913a30d77a1d98e4.7 s4.0 s142 ms
www.delta.com/homepage/26.3.8/mach-core/browser/polyfills.js4.2 s3.4 s11 ms
Unattributable3.5 s868 ms0.0 ms
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB2.1 s1.9 s196 ms
www.delta.com/eu/en1.9 s76 ms12 ms
/NxvV2/ISv/V5F2/Si/veeSUD/wb7hbLaQ/K0ciPAE/UHQfJX/dcDxdt?...1.6 s1.3 s273 ms
tms.delta.com/delta/dl_anderson/Bootstrap.js1.3 s1.1 s210 ms
assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js917 ms671 ms229 ms
www.delta.com/homepage/26.3.8/mach-core/browser/main.js834 ms18 ms800 ms
cdn.cookielaw.org/scripttemplates/202503.1.0/otBannerSdk.js601 ms423 ms86 ms
www.delta.com/akam/13/4addec96292 ms280 ms7.1 ms
s.go-mpulse.net/boomerang/PWV8J-R2M7Y-67AAN-EA9TD-6DRAX244 ms114 ms91 ms
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/wb/d1V3OwE/UmB7Xj/cGAGcp241 ms190 ms50 ms
p11.techlab-cdn.com/e/65226_747628124.js156 ms69 ms16 ms
p11.techlab-cdn.com/e/65319_1825172608.js139 ms104 ms33 ms
www.delta.com/content/dam/delta-applications/login/assets/tracker-3.10.1.js133 ms83 ms35 ms
www.delta.com/106 ms11 ms15 ms
/delta/dl_anderson/serverComponent.php?namespace=TMS&stat...91 ms85 ms1.3 ms
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RC286d4830056d424...90 ms84 ms2.7 ms
/delta/dl_anderson/code/cf11598eb17516b9c2e74b90fe713c9f....86 ms68 ms9.7 ms
/delta/dl_anderson/code/35dd2cfadd08becc64f4d3a87720aaa1....71 ms48 ms20 ms
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RC6d20ec2c5bbb40d...70 ms65 ms1.2 ms
/3b29aa0834b1/0e49b4a4297a/e94de24008a4/RCe7c3c47950ce471...68 ms66 ms0.8 ms
cdn.cookielaw.org/scripttemplates/otSDKStub.js55 ms44 ms9.0 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.

CategoryTime Spent
Script Evaluation15.3 s
Other4.0 s
Script Parsing & Compilation2.3 s
Style & Layout1.2 s
Rendering433 ms
Parse HTML & CSS377 ms
Garbage Collection315 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
The page has an unload handler in the main frame.Actionable
The page has an unload handler in a sub frame.Actionable

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 18.6 KiB
URLTransfer SizeEst Savings
21.1 KiB18.6 KiB

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.

URLTransfer Size
www.delta.com/homepage/26.3.8/mach-core/browser/main.js661.6 KiB
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB172.9 KiB
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB172.8 KiB
/NxvV2/ISv/V5F2/Si/veeSUD/wb7hbLaQ/K0ciPAE/UHQfJX/dcDxdt?...160.1 KiB
www.delta.com/content/dam/delta-tnt/homepage/card-cd/brycecanyon-ut-slc-945.webp151.2 KiB
www.delta.com/content/dam/delta-tnt/homepage/btf/wf-3383622-01-1050x600.webp140.4 KiB
/content/dam/delta-tnt/homepage/hero/2025/Retail/current-...128.6 KiB
/content/dam/delta-tnt/homepage/hero/2025/Retail/current-...125.0 KiB
cdn.cookielaw.org/scripttemplates/202503.1.0/otBannerSdk.js115.9 KiB
assets.adobedtm.com/3b29aa0834b1/0e49b4a4297a/launch-ab7c06f028a9.min.js100.1 KiB

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

●Document request latency
●Optimize DOM size
●Font display
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●Minify JavaScript
●User Timing marks and measures 82 user timings
●Avoid long main-thread tasks 20 long tasks found
●Avoid non-composited animations 1 animated element found
●Image elements have explicit `width` and `height`
●Network Requests
●Network Round Trip Times 100 ms
●Server Backend Latencies 270 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 260 ms
○INP breakdown
94

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.

Names and labels

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.bg-surface-navigation > div.hph-message-content > span.hph-description > a div.bg-surface-navigation > div.hph-message-content > span.hph-description > a

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Best practices

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Explore our current flight deals div.hph-message-content > span.hph-description > span.no-underline > a
and plan your next adventure. div.hph-message-content > span.hph-description > span.no-underline > a

These items highlight common accessibility best practices.

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
AMS Amsterdam, Netherlands idp-book-widget-search-modal-mach-core > div.airport-search-modal > div#one-way-route-picker > button#one-way-route-picker-origin-button
To Destination idp-book-widget-search-modal-mach-core > div.airport-search-modal > div#one-way-route-picker > button#one-way-route-picker-destination-button
Netherlands - English div > idp-language-selector > div#mach-homepage-footer-language-selector-container > a#mach-homepage-footer-language-selector
○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
●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
●`[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
●Form elements have associated labels
●`[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
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links are distinguishable without relying on color.
●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
●Document has a main landmark.
●Deprecated ARIA roles were not used
●Uses ARIA roles only on compatible elements
●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 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
○`<frame>` or `<iframe>` elements have a title
○Heading elements appear in a sequentially-descending order
○`<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
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Skip links are focusable.
○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.
○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.
77

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 / WarningSource
SharedStorage
www.delta.com/content/dam/delta-applications/login/assets/tracker-3.10.1.js line 16, col 201
SharedStorage
www.delta.com/content/dam/delta-applications/login/assets/tracker-3.10.1.js line 16, col 201
Unload event listeners are deprecated and will be removed.
www.delta.com/resources/df032bb95163120c0d0265eb98f27f913a30d77a1d98e line 141, col 127

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.

SourceDescription
A bad HTTP response code (444) was received when fetching the script.
A bad HTTP response code (444) was received when fetching the script.
www.delta.com/akam/13/4addec96
Failed to load resource: the server responded with a status of 404 ()
www.delta.com/eu/en line 37, col 0
Refused to execute script from 'https://www.delta.com/akam/13/4addec96' because its MIME type ('text/html') is not executable, and strict MIME type checking is enabled.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB
www.delta.com/NxvV2/ISv/V5F2/Si/veeSUD/1G7hbLaQkOX7LS/fQUZPAE/fnJiRG/IXEUIB
www.delta.com/homepage/26.3.8/mach-core/browser/main.js
www.delta.com/homepage/26.3.8/mach-core/browser/main.js
●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 clickjacking with XFO or CSP
●Mitigate DOM-based XSS with Trusted Types
●Detected JavaScript libraries
○Redirects HTTP traffic to HTTPS
83

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.

Crawling and Indexing

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
Select other Location and Language div.pop-up-box > div.pop-up-box-content > div.flex > a.link

To appear in search results, crawlers need access to your app.

Content Best Practices

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

Why this matters

Informational: a Permissions-Policy directive showing feature -> allowed origins.

Source: MDN Permissions-Policy

Format your HTML in a way that enables crawlers to better understand your app’s content.

○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
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
○robots.txt is valid

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