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edx.org Mobile Performance
37/100
These metrics represent real-world Chrome users experience viewing edx.org on mobile devices. 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
First Input Delay
Cumulative Layout Shift
First Contentful Paint
Largest Contentful Paint
Metrics
Total Blocking Time2/100 1,970 ms
Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more.
Time to Interactive9/100 14.6 s
Time to interactive is the amount of time it takes for the page to become fully interactive. Learn more.
Cumulative Layout Shift23/100 0.427
Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more.
Largest Contentful Paint38/100 4.5 s
Largest Contentful Paint marks the time at which the largest text or image is painted. Learn More
Speed Index73/100 4.5 s
Speed Index shows how quickly the contents of a page are visibly populated. Learn more.
First Contentful Paint89/100 2.4 s
First Contentful Paint marks the time at which the first text or image is painted. Learn more.
Should Fix (14)
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
2,100 ms
Defer offscreen images
Potential savings of 91 KiB
450 ms
Avoid serving legacy JavaScript to modern browsers
Potential savings of 34 KiB
150 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
Reduce the impact of third-party code
Third-party code blocked the main thread for 460 ms
Avoid `document.write()`
Minimize main-thread work
6.9 s
Serve static assets with an efficient cache policy
17 resources found
Reduce JavaScript execution time
4.3 s
Largest Contentful Paint element
1 element found
Keep request counts low and transfer sizes small
95 requests • 1,479 KiB
Avoid chaining critical requests
3 chains found
Avoid long main-thread tasks
20 long tasks found
Avoid large layout shifts
4 elements found
Passed Audits (18)
Properly size images
Remove unused CSS
Potential savings of 58 KiB
Efficiently encode images
Avoids enormous network payloads
Total size was 1,479 KiB
Avoid multiple page redirects
Potential savings of 630 ms
Minify JavaScript
Avoids an excessive DOM size
481 elements
Eliminate render-blocking resources
Minify CSS
Preload key requests
Avoids large JavaScript libraries with smaller alternatives
0 large libraries found
Uses passive listeners to improve scrolling performance
Initial server response time was short
Root document took 100 ms
Serve images in next-gen formats
Potential savings of 65 KiB
Preconnect to required origins
Use video formats for animated content
Enable text compression
Remove duplicate modules in JavaScript bundles
edx.org Mobile SEO
81/100
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 (3)
Mobile Friendly
Make sure your pages are mobile friendly so users don’t have to pinch or zoom in order to read the content pages. Learn more.
Tap targets are not sized appropriately
30% appropriately sized tap targets
Content Best Practices
Format your HTML in a way that enables crawlers to better understand your app’s content.
Document doesn't have a valid `hreflang`
Links do not have descriptive text
2 links found
Passed Audits (11)
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Document uses legible font sizes
97.18% legible text
Page has successful HTTP status code
Image elements have `[alt]` attributes
Page isn’t blocked from indexing
Document has a valid `rel=canonical`
Document has a meta description
robots.txt is valid
Document has a `<title>` element
Links are crawlable
Document avoids plugins
edx.org Mobile Best Practices
64/100
These checks highlight opportunities to improve the overall code health of edx.org mobile 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 (5)
General
Browser errors were logged to the console
Registers an `unload` listener
Trust and Safety
Includes front-end JavaScript libraries with known security vulnerabilities
1 vulnerability detected
Does not use HTTPS
2 insecure requests found
User Experience
Serves images with low resolution
Passed Audits (11)
Avoids deprecated APIs
Avoids requesting the notification permission on page load
Allows users to paste into password fields
Properly defines charset
Page has the HTML doctype
Avoids Application Cache
Links to cross-origin destinations are safe
Detected JavaScript libraries
Avoids requesting the geolocation permission on page load
Page has valid source maps
Displays images with correct aspect ratio
edx.org Mobile Progressive Web App
21/100
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 provide a valid `apple-touch-icon`
Manifest doesn't have a maskable icon
Does not set a theme color for the address bar.
Fast and reliable
`start_url` does not respond with a 200 when offline
Page load is not fast enough on mobile networks
Interactive at 14.6 s
Current page does not respond with a 200 when offline
Installable
Does not register a service worker that controls page and `start_url`
Does not use HTTPS
2 insecure requests found
Web app manifest does not meet the installability requirements
Passed Audits (4)
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Redirects HTTP traffic to HTTPS
Contains some content when JavaScript is not available
Content is sized correctly for the viewport
edx.org Mobile 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 (26)
Background and foreground colors have a sufficient contrast ratio
`[id]` attributes on active, focusable elements are unique
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
Image elements have `[alt]` attributes
`[aria-*]` attributes have valid values
Form elements have associated labels
`[lang]` attributes have a valid value
The page contains a heading, skip link, or landmark region
`[role]`s are contained by their required parent element
`[role]` values are valid
`[role]`s have all required `[aria-*]` attributes
`<html>` element has a `[lang]` attribute
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
ARIA IDs are unique
`<frame>` or `<iframe>` elements have a title
`[aria-*]` attributes are valid and not misspelled
`<html>` element has a valid value for its `[lang]` attribute
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
No element has a `[tabindex]` value greater than 0
Document has a `<title>` element
`[aria-hidden="true"]` is not present on the document `<body>`
Heading elements appear in a sequentially-descending order
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
`[aria-hidden="true"]` elements do not contain focusable descendents
Links have a discernible name
Buttons have an accessible name
Mobile Usability
97/100
These checks validate how easily a visitor can use edx.org on a mobile device. Test results include a list of any mobile usability problems. Mobile usability problems are issues that can affect a user that visits the page on a mobile (small screen) device, including small font sizes (which are hard to read on a small screen).
Should Fix (1)
Size tap targets appropriately
Passed Audits (4)
Avoid plugins
Configure the viewport
Size content to viewport
Use legible font sizes
Mobile Speed
43/100
These checks analyze the performance of edx.org on mobile 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
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Leverage browser caching
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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