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edx.org Desktop Performance
87/100
These metrics represent real-world Chrome users experience viewing edx.org web page. Reports are focused on loading performance and other critical factors that most affect user experience. Follow our guide to track, optimize, and improve the quality of your web pages.
User Loading Experience
Cumulative Layout Shift
First Input Delay
First Contentful Paint
Largest Contentful Paint
Metrics
Cumulative Layout Shift28/100 0.378
Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more.
Time to Interactive82/100 2.9 s
Time to interactive is the amount of time it takes for the page to become fully interactive. Learn more.
Total Blocking Time87/100 170 ms
Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more.
Largest Contentful Paint91/100 1.2 s
Largest Contentful Paint marks the time at which the largest text or image is painted. Learn More
Speed Index96/100 1.0 s
Speed Index shows how quickly the contents of a page are visibly populated. Learn more.
First Contentful Paint98/100 0.7 s
First Contentful Paint marks the time at which the first text or image is painted. Learn more.
Should Fix (8)
Opportunities
These suggestions can help your page load faster. They don't directly affect the Performance score.
Remove unused JavaScript
Potential savings of 339 KiB
560 ms
Diagnostics
More information about the performance of your application. These numbers don't directly affect the Performance score.
Ensure text remains visible during webfont load
Serve static assets with an efficient cache policy
16 resources found
Avoid large layout shifts
5 elements found
Avoid chaining critical requests
3 chains found
Keep request counts low and transfer sizes small
92 requests • 1,432 KiB
Avoid long main-thread tasks
4 long tasks found
Largest Contentful Paint element
1 element found
Passed Audits (24)
JavaScript execution time
0.7 s
Preconnect to required origins
Eliminate render-blocking resources
Minify CSS
Avoids enormous network payloads
Total size was 1,432 KiB
Uses passive listeners to improve scrolling performance
Serve images in next-gen formats
Potential savings of 22 KiB
Avoids `document.write()`
Avoids large JavaScript libraries with smaller alternatives
0 large libraries found
Properly size images
Potential savings of 5 KiB
Remove duplicate modules in JavaScript bundles
Use video formats for animated content
Minimizes main-thread work
1.5 s
Enable text compression
Avoid serving legacy JavaScript to modern browsers
Potential savings of 34 KiB
Avoids an excessive DOM size
479 elements
Defer offscreen images
Potential savings of 56 KiB
Preload key requests
Initial server response time was short
Root document took 80 ms
Efficiently encode images
Minimize third-party usage
Third-party code blocked the main thread for 10 ms
Minify JavaScript
Remove unused CSS
Potential savings of 57 KiB
Avoid multiple page redirects
Potential savings of 190 ms
edx.org Desktop SEO
83/100
These checks ensure that your page is optimized for search engine results ranking. There are additional factors Lighthouse does not check that may affect your search ranking. Learn more. Run these additional validators on your site to check additional SEO best practices.
Should Fix (2)
Content Best Practices
Format your HTML in a way that enables crawlers to better understand your app’s content.
Links do not have descriptive text
2 links found
Document doesn't have a valid `hreflang`
Passed Audits (10)
Links are crawlable
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Image elements have `[alt]` attributes
Document has a meta description
Document avoids plugins
Document has a valid `rel=canonical`
robots.txt is valid
Page isn’t blocked from indexing
Page has successful HTTP status code
Document has a `<title>` element
edx.org Desktop Best Practices
71/100
These checks highlight opportunities to improve the overall code health of edx.org page. Current recommendations will help to make your page fast and secure, to create a good user experience and to avoid deprecated technologies.
Should Fix (4)
Trust and Safety
Includes front-end JavaScript libraries with known security vulnerabilities
1 vulnerability detected
Does not use HTTPS
1 insecure request found
General
Registers an `unload` listener
Browser errors were logged to the console
Passed Audits (12)
Detected JavaScript libraries
Page has the HTML doctype
Avoids deprecated APIs
Page has valid source maps
Avoids requesting the geolocation permission on page load
Allows users to paste into password fields
Serves images with appropriate resolution
Links to cross-origin destinations are safe
Avoids requesting the notification permission on page load
Displays images with correct aspect ratio
Properly defines charset
Avoids Application Cache
edx.org Desktop Progressive Web App
19/100
These checks validate the aspects of a Progressive Web App. Learn more. These checks are required by the baseline PWA Checklist but are not automatically checked by Lighthouse. They do not affect your score but it's important that you verify them manually.
Should Fix (10)
PWA Optimized
Is not configured for a custom splash screen
Does not set a theme color for the address bar.
Does not provide a valid `apple-touch-icon`
Manifest doesn't have a maskable icon
Fast and reliable
Current page does not respond with a 200 when offline
Page load is not fast enough on mobile networks
Interactive on simulated mobile network at 14.3 s
`start_url` does not respond with a 200 when offline
Installable
Does not register a service worker that controls page and `start_url`
Web app manifest does not meet the installability requirements
Does not use HTTPS
1 insecure request found
Passed Audits (3)
Contains some content when JavaScript is not available
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Redirects HTTP traffic to HTTPS
edx.org Desktop Accessibility
94/100
These checks highlight opportunities to improve the accessibility of your web app. Only a subset of accessibility issues can be automatically detected so manual testing is also encouraged. These items address areas which an automated testing tool cannot cover. Learn more in our guide on conducting an accessibility review.
Should Fix (1)
ARIA
These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.
`[aria-*]` attributes do not match their roles
Passed Audits (25)
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
`[aria-*]` attributes have valid values
No element has a `[tabindex]` value greater than 0
`[role]`s are contained by their required parent element
ARIA IDs are unique
Form elements have associated labels
`[aria-hidden="true"]` elements do not contain focusable descendents
Buttons have an accessible name
`[aria-hidden="true"]` is not present on the document `<body>`
`[role]` values are valid
Heading elements appear in a sequentially-descending order
`[id]` attributes on active, focusable elements are unique
Image elements have `[alt]` attributes
The page contains a heading, skip link, or landmark region
`<html>` element has a `[lang]` attribute
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
`[role]`s have all required `[aria-*]` attributes
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
Links have a discernible name
`<html>` element has a valid value for its `[lang]` attribute
`[lang]` attributes have a valid value
Background and foreground colors have a sufficient contrast ratio
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
`[aria-*]` attributes are valid and not misspelled
Document has a `<title>` element
Desktop Speed
51/100
These checks analyze the performance of edx.org on desktop devices and return PageSpeed score and information on how to improve the load time. What makes a good Progressive Web App?
Should Fix (5)
Optimize images
Leverage browser caching
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Prioritize visible content
Minify JavaScript
Passed Audits (5)
Avoid landing page redirects
Enable compression
Reduce server response time
Minify CSS
Minify HTML
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