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Audit Complete

Results for https://edx.org

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SaaS / Software · estimated Tracking: signups
Netherlands Netherlands · Amsterdam Completed: Apr 15, 2026 23:28 UTC
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Mobile 375 × 812

Screenshot of the audited page (Mobile 375×812)

Desktop 1440 × 900

Screenshot of the audited page (Desktop 1440×900)
C70

Site Health

Score: 70 / 100

Based on 8 categories, 0 sections

Room to improve — your 46.8s load time is above Google's 2.5s 'Good' threshold.

Several missing protections leave your users and data exposed.

Several issues make your site difficult for assistive technology users.

Well-optimized for search — your content is discoverable.

Solid infrastructure — fast server responses across the board.

Mostly compliant — a few items need attention.

Rich content metadata — your pages look great everywhere.

Heavier than average — reducing page weight saves energy and bandwidth.

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

How the composite score is calculated

How you compare

CMS sites average 73
At average
Better than 7% of CMS sites
Amazon Route 53 sites average 72
At average
Better than 14% of Amazon Route 53 sites See full Amazon Route 53 benchmark →

Top Priorities (5)

1

Content-Security-Policy header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers
2

HSTS header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers
3

No Content-Security-Policy header found

Security gaps expose your site and users to attacks, eroding trust.

Security › Content Security Policy
4

Page weighs 22.9 MB (5.4 MB transferred)

Performance issues directly impact user engagement and conversion rates.

Performance › Page Weight Budget
5

1 control(s) without accessible label

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Form Accessibility
View fix priority matrix

Fix Priority Matrix

5 findings

Quick Wins

3

High impact, low effort — start here.

Strategic

2

High impact, requires investment.

Easy Improvements

0

Small gains, minimal effort.

Nothing in this quadrant — good news.

Deprioritize

0

Low impact, high effort — do last.

Nothing in this quadrant — good news.

← Low effort High effort →
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<a href="https://beavercheck.com/results/e683c6a5-9589-4681-bbd0-8114d468e22d"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Fedx.org" alt="BeaverCheck Score"></a>
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What fixing these means

Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. Your LCP of 46.8s exceeds Google's 2.5s 'Good' threshold and the 1 performance issue below directly contributes to it. Accessibility issues exclude users who rely on assistive technology — an estimated 15% of your potential audience. Addressing the critical issues below would have the most immediate impact on your user trust.

3 security gaps detected — browsers may warn visitors about your site.
Your LCP is 46.8s — fixing the 1 performance critical could bring it under Google's 2.5s 'Good' threshold.
1 accessibility issue excludes users who rely on assistive technology.

Return on Investment

€425 investment → €1.25/month returns + EUR 120,500,000 risk avoided

Payback period: > 2 years First-year ROI: -96%

Investment

€425

5h · 5 findings

Monthly returns

€1.25 /mo

~€15 / year

  • Bandwidth savings €1.25

Regulatory risk avoided

EUR 120,500,000

if kept compliant

  • ePrivacy Directive EUR 100,000,000
  • GDPR EUR 20,000,000
  • EAA EUR 500,000

€128 — in quick wins — start here for the fastest payback

Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.

Full methodology & sources

Estimated Remediation Cost

€425

5.0 developer hours at €85/hr

Based on European Union rates (€85/hr)

Quick wins
€128 3 fixes in ~90 minutes

Start here for the best return on investment

Cost by category

Cost by effort level

Adjust assumptions
/hr

Rates reflect fully-loaded developer cost including overhead

How developer rates are sourced

What Inaction Is Costing You

€10,041,668 / month at risk

~€120,500,015 / year if left unfixed

Compliance Risk

€120,500,000

ePrivacy DirectiveGDPREAA
  • No privacy policy link detected
    GDPR: EUR 10,000 – EUR 20,000,000
  • Trackers detected but no cookie policy found
    GDPR: EUR 5,000 – EUR 10,000,000
  • Trackers detected but no cookie policy found
    GDPR: EUR 10,000 – EUR 20,000,000

+8 more

Bandwidth Waste

€1.25 /mo

16855.0 MB/mo × 0.074 EUR/GB

  • Optimize transfer: save ~1.7 MB per page load
    Saves €1.25/mo

Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.

Compliance methodology · SEO assumptions · Bandwidth model

Your performance is already good — improvements may show diminishing returns

Unique monthly visitors from your analytics

Purchases, signups, or key actions

Optional — for revenue estimation

additional conversions/month

more engaged visitors from reduced bounce

potential monthly revenue
Current bounce (est.)
After fixes (est.)
Estimated bounce reduction

Fix 5 critical issues to capture this value

How this is calculated

Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.

Your site's LCP: → estimated after fixes.

These are estimates based on industry research — actual results vary

Bounce-rate model & assumptions

Your data stays in your browser — nothing is sent to our servers

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

18
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

6.48 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

46.77 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

21.32 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.168

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

18.10 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

51.57 s

Detailed Report

Audit breakdown by category with detailed findings.

18

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

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

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.

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:0.024575] map[node:map[boundingRect:map[bottom:2326 height:668 left:0 right:412 top:1658 width:412] lhId:page-1-DIV nodeLabel:Trending on edX Executive Education Featured AI & Digital Transformation Sustai… path:1,HTML,1,BODY,4,DIV,1,MAIN,0,ARTICLE,2,DIV selector:div > main#page-id-3021 > article.container > div.py-8 snippet:<div class="py-8 lg:py-20 mx-break-out flex justify-center bg-putty-100"> type:node] score:0.024575]]
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:0.016437] map[node:map[boundingRect:map[bottom:823 height:307 left:0 right:412 top:516 width:412] lhId:page-4-DIV nodeLabel:We and our partners use cookies to enhance your experience on our site, analyse… path:1,HTML,1,BODY,317,DIV,1,DIV selector:body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk snippet:<div id="onetrust-banner-sdk" class="otFlat bottom ot-wo-title ot-buttons-fw" tabindex="0" role="region" aria-label="Cookie banner" style="bottom: 0px;"> type:node] score:0.006723] map[node:map[boundingRect:map[bottom:823 height:76 left:0 right:412 top:747 width:412] lhId:page-3-IFRAME nodeLabel:Branch Banner Frame path:1,HTML,1,BODY,0,IFRAME selector:body.__className_f367f3 > iframe#branch-banner-iframe snippet:<iframe src="about:blank" scrolling="no" id="branch-banner-iframe" class="branch-animation" aria-label="Branch Banner Frame" style="overflow: hidden; bottom: 0px;"> type:node] score:0.004606] map[node:map[boundingRect:map[bottom:823 height:76 left:0 right:412 top:747 width:412] lhId:page-3-IFRAME nodeLabel:Branch Banner Frame path:1,HTML,1,BODY,0,IFRAME selector:body.__className_f367f3 > iframe#branch-banner-iframe snippet:<iframe src="about:blank" scrolling="no" id="branch-banner-iframe" class="branch-animation" aria-label="Branch Banner Frame" style="overflow: hidden; bottom: 0px;"> type:node] score:0.002818] map[node:map[boundingRect:map[bottom:823 height:307 left:0 right:412 top:516 width:412] lhId:page-4-DIV nodeLabel:We and our partners use cookies to enhance your experience on our site, analyse… path:1,HTML,1,BODY,317,DIV,1,DIV selector:body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk snippet:<div id="onetrust-banner-sdk" class="otFlat bottom ot-wo-title ot-buttons-fw" tabindex="0" role="region" aria-label="Cookie banner" style="bottom: 0px;"> type:node] score:0.001156] map[node:map[boundingRect:map[bottom:823 height:307 left:0 right:412 top:516 width:412] lhId:page-4-DIV nodeLabel:We and our partners use cookies to enhance your experience on our site, analyse… path:1,HTML,1,BODY,317,DIV,1,DIV selector:body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk snippet:<div id="onetrust-banner-sdk" class="otFlat bottom ot-wo-title ot-buttons-fw" tabindex="0" role="region" aria-label="Cookie banner" style="bottom: 0px;"> type:node] score:0.001134]]
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:0.035997] map[node:map[boundingRect:map[bottom:823 height:307 left:0 right:412 top:516 width:412] lhId:page-4-DIV nodeLabel:We and our partners use cookies to enhance your experience on our site, analyse… path:1,HTML,1,BODY,317,DIV,1,DIV selector:body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk snippet:<div id="onetrust-banner-sdk" class="otFlat bottom ot-wo-title ot-buttons-fw" tabindex="0" role="region" aria-label="Cookie banner" style="bottom: 0px;"> type:node] score:0.035997]]
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:0.167697] map[node:map[boundingRect:map[bottom:1658 height:120 left:16 right:396 top:1538 width:380] lhId:page-5-DIV nodeLabel:Next slide path:1,HTML,1,BODY,4,DIV,1,MAIN,0,ARTICLE,1,DIV selector:div > main#page-id-3021 > article.container > div.py-1 snippet:<div class="py-1"> type:node] score:0.167697]]

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.

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:118.354 source:map[column:51496 line:1 type:source-location url:https://www.edx.org/_next/static/chunks/31684-c747813ca79ce5e5.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:5.179 source:map[column:60234 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/94285-58c8714c348a9f22.js urlProvider:network]] map[reflowTime:41.311 source:map[column:302174 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/34713-2dc09c03d2c34781.js urlProvider:network]] map[reflowTime:55.097 source:map[type:text value:[unattributed]]] map[reflowTime:1.333 source:map[column:19436 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/45618.b1cc06f52ae589f0.js urlProvider:network]] map[reflowTime:4.178 source:map[column:40384 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/45618.b1cc06f52ae589f0.js urlProvider:network]] map[reflowTime:1.828 source:map[column:332 line:412 type:source-location url:https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js urlProvider:network]] map[reflowTime:0.648 source:map[column:55 line:936 type:source-location url:https://www.googletagmanager.com/gtag/js?id=G-D3KS4KMDT0&cx=c&gtm=4e64e1 urlProvider:network]] map[reflowTime:26.001 source:map[column:260578 line:6 type:source-location url:https://beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:1.207 source:map[column:39959 line:6 type:source-location url:https://beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:10.285 source:map[column:148983 line:6 type:source-location url:https://beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:88.52 source:map[column:17508 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/58355-0a989aab31f5c1e2.js urlProvider:network]] map[reflowTime:24.921 source:map[column:17570 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/13542-c6a4f9991134f550.js urlProvider:network]] map[reflowTime:0.891 source:map[column:314061 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/34713-2dc09c03d2c34781.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:634.9370001220703 label:Time to first byte subpart:timeToFirstByte] map[duration:11249.98199987793 label:Resource load delay subpart:resourceLoadDelay] map[duration:59.12 label:Resource load duration subpart:resourceLoadDuration] map[duration:38.572 label:Element render delay subpart:elementRenderDelay]]
lhId: page-0-IMG
nodeLabel: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
path: 1,HTML,1,BODY,4,DIV,1,MAIN,0,ARTICLE,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,IMG
selector: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
snippet: <img alt="" data-ot-ignore="" fetchpriority="high" loading="lazy" decoding="async" data-nimg="fill" class="optanon-category-C0001 object-cover object-right relative z-[-1] m-0 sm:hi…" sizes="100vw" srcset="/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattachment-27642Backgr…" src="https://www.edx.org/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fatt…" style="position: absolute; height: 100%; width: 100%; inset: 0px;">

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: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
path: 1,HTML,1,BODY,4,DIV,1,MAIN,0,ARTICLE,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,IMG
selector: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
snippet: <img alt="" data-ot-ignore="" fetchpriority="high" loading="lazy" decoding="async" data-nimg="fill" class="optanon-category-C0001 object-cover object-right relative z-[-1] m-0 sm:hi…" sizes="100vw" srcset="/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattachment-27642Backgr…" src="https://www.edx.org/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fatt…" style="position: absolute; height: 100%; width: 100%; inset: 0px;">

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

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.

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
div.container > div.lg:ml-auto > div.w-full > img.optanon-category-C0001 div.container > div.lg:ml-auto > div.w-full > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattac...56.7 KiB38.7 KiB
AI for Everyone: Master the Basics a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...41.2 KiB21.6 KiB
Supply Chain Fundamentals. a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...28.0 KiB8.4 KiB
div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001 div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattac...17.5 KiB5.9 KiB

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

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.

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: 754 ms
URLTime Spent
edx.org/754 ms
www.edx.org/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.

ElementLayout shift score
Next slide div > main#page-id-3021 > article.container > div.py-1
0.168
We and our partners use cookies to enhance your experience on our site, analyse… body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.036
Trending on edX Executive Education Featured AI & Digital Transformation Sustai… div > main#page-id-3021 > article.container > div.py-8
0.025
We and our partners use cookies to enhance your experience on our site, analyse… body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.007
Branch Banner Frame body.__className_f367f3 > iframe#branch-banner-iframe
0.005
Branch Banner Frame body.__className_f367f3 > iframe#branch-banner-iframe
0.003
We and our partners use cookies to enhance your experience on our site, analyse… body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001
We and our partners use cookies to enhance your experience on our site, analyse… body.__className_f367f3 > div#onetrust-consent-sdk > div#onetrust-banner-sdk
0.001

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: 2.0 s 391.6 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

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Estimated savings: 11.1 s 1.8 MiB
URLTransfer SizeEst Savings
www.edx.org/_next/static/chunks/77035-cd6004d04665d287.js560.3 KiB448.7 KiB
www.edx.org/_next/static/chunks/82c1a80d-ae299923ae10f5b2.js226.0 KiB191.0 KiB
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js361.8 KiB177.0 KiB
www.edx.org/_next/static/chunks/4cde4f2d-a6ae58bcb4c8999f.js143.3 KiB141.5 KiB
www.edx.org/_next/static/chunks/a4634e51-e0ea9966714daeda.js117.9 KiB112.3 KiB
www.googletagmanager.com/gtm.js?id=GTM-543ZGMK2166.1 KiB79.7 KiB
www.edx.org/_next/static/chunks/aaea2bcf-fcf14465037c204e.js99.3 KiB70.2 KiB
www.googletagmanager.com/gtag/js?id=G-D3KS4KMDT0&cx=c&gtm=4e64e1179.8 KiB68.2 KiB
beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js109.7 KiB66.2 KiB
www.edx.org/_next/static/chunks/34713-2dc09c03d2c34781.js93.3 KiB62.2 KiB
www.edx.org/_next/static/chunks/10c000c1-820b48e60ecf9a58.js55.7 KiB55.6 KiB
www.edx.org/_next/static/chunks/4a5bd2f9-11d23ed2fab7c94c.js61.2 KiB54.7 KiB
www.edx.org/_next/static/chunks/ae064d6e-be7bdf3c6845b5d3.js58.6 KiB53.7 KiB
www.edx.org/_next/static/chunks/18192-00429a85436192b6.js68.7 KiB46.7 KiB
www.edx.org/_next/static/chunks/56827-2aa3be22f6d464ca.js64.4 KiB41.8 KiB
www.edx.org/_next/static/chunks/b8ba6eb2-3ac6594aa448865d.js51.3 KiB39.5 KiB
www.edx.org/_next/static/chunks/6150e6b2-d454fae9bf4565bd.js47.8 KiB33.8 KiB
www.edx.org/_next/static/chunks/94466-1f4eaaf7e4c46361.js47.7 KiB24.8 KiB
www.edx.org/_next/static/chunks/d648eb28-f98479d2cde4bc66.js24.3 KiB21.6 KiB
www.edx.org/_next/static/chunks/8cc6faea-d4a5213af5d556c9.js25.6 KiB20.9 KiB
www.edx.org/_next/static/chunks/68097-7170da9a8c8e222a.js22.8 KiB20.4 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.edx.org/_next/static/chunks/31684-c747813ca79ce5e5.js27.2 s25.9 s26 ms
www.edx.org/6.5 s1.2 s607 ms
Unattributable1.9 s89 ms0.0 ms
www.edx.org/_next/static/chunks/77035-cd6004d04665d287.js1.7 s1.4 s290 ms
www.edx.org/_next/static/chunks/4bd1b696-8114277e1a0c5c1d.js1.4 s1.0 s53 ms
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js927 ms634 ms142 ms
www.googletagmanager.com/gtag/js?id=G-D3KS4KMDT0&cx=c&gtm=4e64e1768 ms553 ms98 ms
www.googletagmanager.com/gtm.js?id=GTM-543ZGMK2701 ms604 ms84 ms
www.edx.org/_next/static/css/c1a0daa9433fa738.css584 ms0.0 ms0.0 ms
beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js472 ms230 ms80 ms
www.edx.org/beam.js362 ms319 ms21 ms
js-agent.newrelic.com/nr-spa-1.312.1.min.js334 ms270 ms20 ms
www.edx.org/api/auto-block?id=fa169e97-be64-4cc1-bad3-9534590f9a30286 ms131 ms130 ms
www.edx.org/_next/static/chunks/21307-8f0e72a894fab571.js284 ms280 ms2.9 ms
www.edx.org/_next/static/chunks/34713-2dc09c03d2c34781.js202 ms19 ms60 ms
www.edx.org/_next/static/chunks/45618.b1cc06f52ae589f0.js174 ms113 ms14 ms
www.edx.org/_next/static/chunks/82c1a80d-ae299923ae10f5b2.js113 ms1.1 ms111 ms
beam.edx.org/scripttemplates/otSDKStub.js96 ms73 ms5.4 ms
www.edx.org/_next/static/chunks/43145-424523c8bdc43658.js89 ms83 ms6.2 ms
sonic-ui.highereducation.com/latest/ucl.adapter.js84 ms30 ms52 ms
www.edx.org/_next/static/chunks/10c000c1-820b48e60ecf9a58.js67 ms1.1 ms65 ms
www.edx.org/_next/static/chunks/a4634e51-e0ea9966714daeda.js58 ms1.0 ms57 ms
www.edx.org/_next/static/chunks/4cde4f2d-a6ae58bcb4c8999f.js58 ms0.9 ms56 ms
/_r?sdk=web2.86.4&branch_key=key_live_kpxBY7wsvq7tp8eu5TH...54 ms41 ms0.5 ms
www.edx.org/_next/static/chunks/94285-58c8714c348a9f22.js50 ms13 ms10 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 Evaluation33.4 s
Other5.0 s
Script Parsing & Compilation2.4 s
Style & Layout2.1 s
Parse HTML & CSS1.2 s
Garbage Collection815 ms
Rendering422 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
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

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

Optimize DOM size
Font display
Modern HTTP
Optimize viewport for mobile
Minify CSS
Minify JavaScript
User Timing marks and measures 5 user timings
Avoid long main-thread tasks 20 long tasks found
Avoid non-composited animations 2 animated elements found
Image elements have explicit `width` and `height`
Network Requests
Network Round Trip Times 90 ms
Server Backend Latencies 280 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Initial server response time was short Root document took 50 ms
INP breakdown
96

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.

Contrast

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Decline Optional Cookies div.ot-sdk-row > div#onetrust-button-group-parent > div#onetrust-button-group > button#onetrust-reject-all-handler
Accept All Cookies div.ot-sdk-row > div#onetrust-button-group-parent > div#onetrust-button-group > button#onetrust-accept-btn-handler

These are opportunities to improve the legibility of your content.

Navigation

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Computer Science div.text-base > div.flex > a.no-underline > h4.elm-h5

These are opportunities to improve keyboard navigation in your application.

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
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
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
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
Select elements have associated label elements.
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
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.
Document has a main landmark.
Deprecated ARIA roles were not used
ARIA IDs are unique
All heading elements contain content.
`[accesskey]` values are unique
`button`, `link`, and `menuitem` elements have accessible names
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
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
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>`.
Uses ARIA roles only on compatible elements
Image elements do not have `[alt]` attributes that are redundant text.
Identical links have the same purpose.
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.
96

Best Practices

General

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
Failed to load resource: the server responded with a status of 401 ()
Failed to load resource: the server responded with a status of 401 ()

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.

URLMap URL
www.edx.org/api/auto-block?id=fa169e97-be64-4cc1-bad3-9534590f9a30
www.edx.org/
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www.edx.org/_next/static/chunks/app/%5Blocale%5D/not-found-bf6d0ab4967ed478.js/_next/static/chunks/app/[locale]/not-found-bf6d0ab4967ed...
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sonic-ui.highereducation.com/latest/ucl.publisher.jssonic-ui.highereducation.com/latest/ucl.publisher.js.map
sonic-ui.highereducation.com/latest/ucl.adapter.jssonic-ui.highereducation.com/latest/ucl.adapter.js.map
Uses HTTPS
Avoids deprecated APIs
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
Redirects HTTP traffic to HTTPS
Mitigate clickjacking with XFO or CSP
Detected JavaScript libraries
92

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.

Content Best Practices

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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 are crawlable
robots.txt is valid
Image elements have `[alt]` attributes
Document has a valid `hreflang`
Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

31
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.33 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

10.12 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

4.93 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.048

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

6.73 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

11.03 s

Detailed Report

Audit breakdown by category with detailed findings.

31

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

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

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.

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.

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:127.84 source:map[column:51496 line:1 type:source-location url:https://www.edx.org/_next/static/chunks/31684-c747813ca79ce5e5.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:31.373 source:map[type:text value:[unattributed]]] map[reflowTime:12.184 source:map[column:60234 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/94285-58c8714c348a9f22.js urlProvider:network]] map[reflowTime:58.696 source:map[column:302174 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/34713-2dc09c03d2c34781.js urlProvider:network]] map[reflowTime:2.319 source:map[column:380 line:580 type:source-location url:https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js urlProvider:network]] map[reflowTime:0.696 source:map[column:47 line:303 type:source-location url:https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js urlProvider:network]] map[reflowTime:0.776 source:map[column:50769 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/45618.b1cc06f52ae589f0.js urlProvider:network]] map[reflowTime:1.013 source:map[column:21 line:718 type:source-location url:https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js urlProvider:network]] map[reflowTime:0.811 source:map[column:376 line:890 type:source-location url:https://www.googletagmanager.com/gtag/js?id=G-D3KS4KMDT0&cx=c&gtm=4e64e1 urlProvider:network]] map[reflowTime:1.103 source:map[column:332 line:412 type:source-location url:https://www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js urlProvider:network]] map[reflowTime:19.86 source:map[column:260578 line:6 type:source-location url:https://beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:19.825 source:map[column:148983 line:6 type:source-location url:https://beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js urlProvider:network]] map[reflowTime:155.219 source:map[column:17508 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/58355-0a989aab31f5c1e2.js urlProvider:network]] map[reflowTime:1.654 source:map[column:314061 line:0 type:source-location url:https://www.edx.org/_next/static/chunks/34713-2dc09c03d2c34781.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:635.7910001220703 label:Time to first byte subpart:timeToFirstByte] map[duration:11833.26399987793 label:Resource load delay subpart:resourceLoadDelay] map[duration:62.601 label:Resource load duration subpart:resourceLoadDuration] map[duration:301.204 label:Element render delay subpart:elementRenderDelay]]
lhId: page-0-IMG
nodeLabel: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
path: 1,HTML,1,BODY,3,DIV,1,MAIN,0,ARTICLE,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,2,IMG
selector: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
snippet: <img alt="" data-ot-ignore="" fetchpriority="high" loading="lazy" decoding="async" data-nimg="fill" class="optanon-category-C0001 object-cover object-right relative z-[-1] m-0 hidde…" sizes="100vw" srcset="/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattachment-27642Backgr…" src="https://www.edx.org/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fatt…" style="position: absolute; height: 100%; width: 100%; inset: 0px;">

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: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
path: 1,HTML,1,BODY,3,DIV,1,MAIN,0,ARTICLE,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,2,IMG
selector: div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
snippet: <img alt="" data-ot-ignore="" fetchpriority="high" loading="lazy" decoding="async" data-nimg="fill" class="optanon-category-C0001 object-cover object-right relative z-[-1] m-0 hidde…" sizes="100vw" srcset="/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattachment-27642Backgr…" src="https://www.edx.org/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fatt…" style="position: absolute; height: 100%; width: 100%; inset: 0px;">

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

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
div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001 div.embla__container > div.embla__slide > div.relative > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattac...66.1 KiB24.3 KiB
Undergraduate Certificate in Artificial Intelligence a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...23.2 KiB16.3 KiB
div.container > div.lg:ml-auto > div.w-full > img.optanon-category-C0001 div.container > div.lg:ml-auto > div.w-full > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fimages.cdn.edx.org%2Fattac...24.1 KiB13.8 KiB
MBA Essentials a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...16.9 KiB9.6 KiB
AI for Everyone: Master the Basics a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...16.3 KiB8.3 KiB
Supply Chain Fundamentals. a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...15.3 KiB8.3 KiB
Why Data Analytics Matters a.h-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...15.1 KiB7.2 KiB
Supply Chain Design. a.h-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...13.3 KiB5.4 KiB
AI Developer a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...12.3 KiB5.0 KiB
Artificial Intelligence Programme a.w-full > div.text-card-foreground > div.flex > img.optanon-category-C0001
/_next/image?url=https%3A%2F%2Fprod-discovery.edx-cdn.org...11.6 KiB4.5 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.

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: 205 ms
URLTime Spent
edx.org/205 ms
www.edx.org/0.0 ms

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 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: 280 ms 390.6 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

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Estimated savings: 1.9 s 1.8 MiB
URLTransfer SizeEst Savings
www.edx.org/_next/static/chunks/77035-cd6004d04665d287.js560.2 KiB448.7 KiB
www.edx.org/_next/static/chunks/82c1a80d-ae299923ae10f5b2.js226.0 KiB191.0 KiB
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js361.8 KiB177.0 KiB
www.edx.org/_next/static/chunks/4cde4f2d-a6ae58bcb4c8999f.js143.3 KiB141.5 KiB
www.edx.org/_next/static/chunks/a4634e51-e0ea9966714daeda.js117.9 KiB112.3 KiB
www.googletagmanager.com/gtm.js?id=GTM-543ZGMK2166.1 KiB79.7 KiB
www.edx.org/_next/static/chunks/aaea2bcf-fcf14465037c204e.js99.3 KiB70.2 KiB
www.googletagmanager.com/gtag/js?id=G-D3KS4KMDT0&cx=c&gtm=4e64e1179.8 KiB68.2 KiB
beam.edx.org/scripttemplates/202407.2.0/otBannerSdk.js109.7 KiB66.2 KiB
www.edx.org/_next/static/chunks/34713-2dc09c03d2c34781.js93.3 KiB62.1 KiB
www.edx.org/_next/static/chunks/10c000c1-820b48e60ecf9a58.js55.7 KiB55.6 KiB
www.edx.org/_next/static/chunks/4a5bd2f9-11d23ed2fab7c94c.js61.2 KiB54.7 KiB
www.edx.org/_next/static/chunks/ae064d6e-be7bdf3c6845b5d3.js58.6 KiB53.7 KiB
www.edx.org/_next/static/chunks/18192-00429a85436192b6.js68.7 KiB44.7 KiB
www.edx.org/_next/static/chunks/56827-2aa3be22f6d464ca.js64.4 KiB41.8 KiB
www.edx.org/_next/static/chunks/b8ba6eb2-3ac6594aa448865d.js51.3 KiB39.5 KiB
www.edx.org/_next/static/chunks/6150e6b2-d454fae9bf4565bd.js47.8 KiB33.8 KiB
www.edx.org/_next/static/chunks/94466-1f4eaaf7e4c46361.js47.7 KiB24.8 KiB
www.edx.org/_next/static/chunks/d648eb28-f98479d2cde4bc66.js24.3 KiB21.6 KiB
www.edx.org/_next/static/chunks/8cc6faea-d4a5213af5d556c9.js25.6 KiB20.9 KiB
www.edx.org/_next/static/chunks/68097-7170da9a8c8e222a.js22.8 KiB20.4 KiB

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Script Evaluation9.2 s
Other1.2 s
Style & Layout705 ms
Script Parsing & Compilation671 ms
Parse HTML & CSS294 ms
Garbage Collection220 ms
Rendering119 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
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

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

Layout shift culprits
Optimize DOM size
Font display
Modern HTTP
Optimize viewport for mobile
Minify CSS
Minify JavaScript
User Timing marks and measures 5 user timings
Avoid long main-thread tasks 20 long tasks found
Avoid non-composited animations 2 animated elements found
Image elements have explicit `width` and `height`
Network Requests
Network Round Trip Times 90 ms
Server Backend Latencies 300 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Initial server response time was short Root document took 50 ms
Avoid large layout shifts 13 layout shifts found
INP breakdown
96

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.

Contrast

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Decline Optional Cookies div.ot-sdk-row > div#onetrust-button-group-parent > div#onetrust-button-group > button#onetrust-reject-all-handler
Accept All Cookies div.ot-sdk-row > div#onetrust-button-group-parent > div#onetrust-button-group > button#onetrust-accept-btn-handler

These are opportunities to improve the legibility of your content.

Navigation

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Computer Science div.text-base > div.flex > a.no-underline > h4.elm-h5

These are opportunities to improve keyboard navigation in your application.

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
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
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.
Select elements have associated label elements.
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
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.
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.
Document has a main landmark.
Deprecated ARIA roles were not used
ARIA IDs are unique
All heading elements contain content.
Identical links have the same purpose.
`[accesskey]` values are unique
`button`, `link`, and `menuitem` elements have accessible names
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
No form fields have multiple labels
`<frame>` or `<iframe>` elements have a title
`<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
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>`.
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.
96

Best Practices

General

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
Failed to load resource: the server responded with a status of 401 ()
Failed to load resource: the server responded with a status of 401 ()

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.

URLMap URL
www.edx.org/api/auto-block?id=fa169e97-be64-4cc1-bad3-9534590f9a30
www.edx.org/
www.edx.org/_next/static/chunks/webpack-a94bbd5414b620ac.jswww.edx.org/_next/static/chunks/webpack-a94bbd5414b620ac.js.map
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www.edx.org/_next/static/chunks/main-app-53c3f9f4fa7e7bfb.jswww.edx.org/_next/static/chunks/main-app-53c3f9f4fa7e7bfb.js.map
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Uses HTTPS
Avoids deprecated APIs
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
Redirects HTTP traffic to HTTPS
Mitigate clickjacking with XFO or CSP
Detected JavaScript libraries
92

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.

Content Best Practices

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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 are crawlable
robots.txt is valid
Image elements have `[alt]` attributes
Document has a valid `hreflang`
Document has a valid `rel=canonical`

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