Lighthouse Mobile
· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.Detailed Report
Audit breakdown by category with detailed findings.
Performance
Insights
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.
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
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.
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.
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.
Performance issues directly impact user engagement and conversion rates.
Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.
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.
Performance issues directly impact user engagement and conversion rates.
Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading
Performance issues directly impact user engagement and conversion rates.
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.
Performance issues directly impact user engagement and conversion rates.
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.
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.
Performance issues directly impact user engagement and conversion rates.
| Request | Cache TTL | Transfer Size |
|---|---|---|
| dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-solid-900.woff2 | 604800.0 s | 253.8 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/css/fontawesome.min.css | 604800.0 s | 138.7 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-brands-400.woff2 | 604800.0 s | 99.4 KiB |
| global.localizecdn.com/localize.js | 259200.0 s | 27.1 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/css/brands.min.css | 604800.0 s | 15.3 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/css/custom-icons.min.css | 604800.0 s | 2.6 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/css/duotone.min.css | 604800.0 s | 1.9 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/css/regular.min.css | 604800.0 s | 1.2 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/css/solid.min.css | 604800.0 s | 1.2 KiB |
Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size
Performance issues directly impact user engagement and conversion rates.
| URL | Resource Size | Est Savings | |
|---|---|---|---|
div.cf-fe544dd2deb4dddb8ba27b4b4f5679ea > div.cf-d442defc83cbe049355e312f4bc523d4 > figure.image--hasRoundedCorners > img.mui-t3ax9v div.cf-fe544dd2deb4dddb8ba27b4b4f5679ea > div.cf-d442defc83cbe049355e312f4bc523d4 > figure.image--hasRoundedCorners > img.mui-t3ax9v | /_next/image?url=https%3A%2F%2Fcontentful-images.code.org... | 59.3 KiB | 48.1 KiB |
HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.
Performance issues directly impact user engagement and conversion rates.
These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.
Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.
Performance issues directly impact user engagement and conversion rates.
| URL | Time Spent |
|---|---|
| code.org/ | 830 ms |
| code.org/en-US | 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
Performance issues directly impact user engagement and conversion rates.
| Element | Layout shift score |
|---|---|
WHO WE ARE
We are the experts in preparing students for an AI-driven world.
C… body > main > div.cf-69444be9a7e4f01e0cabcf50af08d6e9 | 0.284 |
div.cf-5c1c11cc9d6348b9402354ba1afa6063 > div.cf-92267537f53a65bb63c5bb229c0cd918 > div.cf-fe544dd2deb4dddb8ba27b4b4f5679ea > ::after div.cf-5c1c11cc9d6348b9402354ba1afa6063 > div.cf-92267537f53a65bb63c5bb229c0cd918 > div.cf-fe544dd2deb4dddb8ba27b4b4f5679ea > ::after | 0.021 |
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.
Performance issues directly impact user engagement and conversion rates.
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.
Performance issues directly impact user engagement and conversion rates.
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.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| www.googletagmanager.com/gtag/js?id=G-L9HT5MZ3HD | 178.1 KiB | 67.7 KiB |
| code.org/_next/static/chunks/326-7f1023f63cd41f9f.js | 67.7 KiB | 34.9 KiB |
| code.org/_next/static/chunks/5670-318ba52a6b4cab24.js | 57.5 KiB | 34.2 KiB |
| /_next/static/chunks/app/[brand]/[locale]/[[...paths]]/pa... | 65.2 KiB | 23.7 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.
Performance issues directly impact user engagement and conversion rates.
| URL | Total CPU Time | Script Evaluation | Script Parse |
|---|---|---|---|
| code.org/_next/static/chunks/1902-09bbc0137809353d.js | 1.8 s | 1.7 s | 12 ms |
| code.org/en-US | 845 ms | 16 ms | 87 ms |
| Unattributable | 485 ms | 15 ms | 0.0 ms |
| code.org/_next/static/chunks/4445.c2d7ef35f9eae3f6.js | 413 ms | 282 ms | 5.0 ms |
| www.googletagmanager.com/gtag/js?id=G-L9HT5MZ3HD | 322 ms | 275 ms | 39 ms |
| code.org/_next/static/chunks/webpack-7a387c03fc9bc55e.js | 228 ms | 226 ms | 1.5 ms |
| code.org/_next/static/chunks/326-7f1023f63cd41f9f.js | 207 ms | 3.9 ms | 18 ms |
| code.org/_next/static/chunks/5670-318ba52a6b4cab24.js | 184 ms | 164 ms | 20 ms |
| code.org/_next/static/chunks/87c73c54-095cf9a90cf9ee03.js | 151 ms | 138 ms | 13 ms |
| code.org/_next/static/chunks/7450.c23ebe5a26c30870.js | 94 ms | 90 ms | 1.9 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
Performance issues directly impact user engagement and conversion rates.
| Category | Time Spent |
|---|---|
| Script Evaluation | 3.0 s |
| Other | 828 ms |
| Style & Layout | 646 ms |
| Script Parsing & Compilation | 301 ms |
| Parse HTML & CSS | 138 ms |
| Garbage Collection | 92 ms |
| Rendering | 79 ms |
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.
Performance issues directly impact user engagement and conversion rates.
| URL | Transfer Size | Est Savings |
|---|---|---|
| dsco.code.org/assets/font-awesome-pro/1764885473/css/fontawesome.min.css | 138.1 KiB | 136.5 KiB |
| dsco.code.org/assets/font-awesome-pro/1764885473/css/brands.min.css | 14.7 KiB | 14.4 KiB |
| .mui-tyipns{background-color:var(--background-neutral-primary-inverse); … } … | 13.1 KiB | 10.4 KiB |
Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions
Performance issues directly impact user engagement and conversion rates.
| URL | |
|---|---|
Powered by AWS Cloud Computing footer.mui-tyipns > div.MuiGrid-root > a.MuiTypography-root > img | code.org/_next/static/media/powered-by-aws.f274900a.webp |
More information about the performance of your application. These numbers don't directly affect the Performance score.
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.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
WHO WE ARE div.cf-4c41f6a4d0f6d9764d017cb615a0857c > div.cf-97f92044dc40a2f5f0093c31861b9841 > div.cf-c3206da2b9ad45bfcd0bb3b3549acb47 > p.MuiTypography-root |
FLAGSHIP WORK section.section-background-secondary > div.MuiContainer-root > div.cf-ad95f457ade13bd9c8fd2226396dce62 > p.MuiTypography-root |
OUR SUPPORTERS div.cf-8b4434df2a9778b5ef0b45338ad7044d > div.cf-98672fd7b4fe05d51c848acf6d8959b1 > div.cf-d6e4617d602895b466c7440880251b1f > p.MuiTypography-root |
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.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Curriculum for the AI era div.cf-a7c8dbcf2b8e47039ae8d687b4f06d99 > div.cf-63e35c8243004acac65b04828fdd9a47 > div.cf-f6a86e00f23d5ad8f796977a686bc25c > h4.MuiTypography-root |
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.
Performance issues directly impact user engagement and conversion rates.
| Failing Elements |
|---|
Learn about Code.org div.cf-97f92044dc40a2f5f0093c31861b9841 > div.cf-5171f0cd3bd370039acfda30d9bd4c01 > div.cf-19fa17c745ec096b6396c78685291e49 > a.genericButton-module__button___-ZvEw |
Explore more stats div.cf-97f92044dc40a2f5f0093c31861b9841 > div.cf-5171f0cd3bd370039acfda30d9bd4c01 > div.cf-793ea3ccffb5860a2e85fc3fc0a1a02e > a.genericButton-module__button___-ZvEw |
Partner with us div.cf-c75c47033e830504de35b5df5840ea5f > div.cf-1664d88001345c4955b130e4604c0a1d > div.cf-d63c92cb905caad3d90b4c391c27ebc8 > a.genericButton-module__button___-ZvEw |
Explore curriculum catalog div.cf-503a38a75061122bc5d2aa1222d3213a > div.cf-a318afa9f3a81b1b7a0bb62e50593924 > div.cf-8fef7fbb8527341d663afedbed841ef3 > a.genericButton-module__button___-ZvEw |
Get started now div.cf-6d9929e522f0aa34377f6efce0f8c247 > div.cf-25973a64a5784700b2a80e055ebfcfb5 > div.cf-883b8fa4bbcfcecabbee156469550e16 > a.genericButton-module__button___-ZvEw |
Read the Framework div.cf-81eb36cf5c15490dae991c5d843279a1 > div.cf-670a77c1bf4aec010c56b582328319f6 > div.cf-4a29891aecab19aa62b4e710ca426272 > a.genericButton-module__button___-ZvEw |
Meet our supporters div.cf-8b4434df2a9778b5ef0b45338ad7044d > div.cf-98672fd7b4fe05d51c848acf6d8959b1 > div.cf-ae51a5a9e52d3cdce5283a41fb9a6798 > a.genericButton-module__button___-ZvEw |
Sign up for free section.section-background-patternPrimary > div.MuiContainer-root > div.cf-3c6501cbcaeb07b42da6b85d8ed7c835 > a.genericButton-module__button___-ZvEw |
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
Performance issues directly impact user engagement and conversion rates.
| Source | Description |
|---|---|
[object Event] |
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.
Performance issues directly impact user engagement and conversion rates.
| URL |
|---|
| code.org/en-US |
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.