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Lighthouse Desktop

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

Audit breakdown by category with detailed findings.

95

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLEst Savings
dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-solid-900.woff275 ms
dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-brands-400.woff245 ms

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:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:82.901 source:map[type:text value:[unattributed]]]]

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.cf-fe544dd2deb4dddb8ba27b4b4f5679ea > div.cf-d442defc83cbe049355e312f4bc523d4 > figure.mui-1c10u4r > img.mui-t3ax9v div.cf-fe544dd2deb4dddb8ba27b4b4f5679ea > div.cf-d442defc83cbe049355e312f4bc523d4 > figure.mui-1c10u4r > img.mui-t3ax9v
/_next/image?url=https%3A%2F%2Fcontentful-images.code.org...59.3 KiB54.5 KiB
div.cf-c8b92fcfae6c8e2f89c239f16ce0580f > div.cf-4f32cd0c22d3e721f89c11ea630f7894 > figure.image--hasRoundedCorners > img.mui-t3ax9v div.cf-c8b92fcfae6c8e2f89c239f16ce0580f > div.cf-4f32cd0c22d3e721f89c11ea630f7894 > figure.image--hasRoundedCorners > img.mui-t3ax9v
/_next/image?url=https%3A%2F%2Fcontentful-images.code.org...51.5 KiB49.6 KiB
div.cf-94e9c4b3889d8ef68f2e07b9b3d20876 > div.cf-21ae972b34af61357b4c01b59eede86a > figure.image--hasRoundedCorners > img.mui-t3ax9v div.cf-94e9c4b3889d8ef68f2e07b9b3d20876 > div.cf-21ae972b34af61357b4c01b59eede86a > figure.image--hasRoundedCorners > img.mui-t3ax9v
/_next/image?url=https%3A%2F%2Fcontentful-images.code.org...17.8 KiB15.4 KiB
div.cf-e1f3f1c9a6352ed29ec0ee3d002cd7e8 > div.cf-37fb84308ab20792fae9b81791f19e7c > figure.image--hasRoundedCorners > img.mui-t3ax9v div.cf-e1f3f1c9a6352ed29ec0ee3d002cd7e8 > div.cf-37fb84308ab20792fae9b81791f19e7c > figure.image--hasRoundedCorners > img.mui-t3ax9v
/_next/image?url=https%3A%2F%2Fcontentful-images.code.org...12.4 KiB12.4 KiB
Powered by AWS Cloud Computing footer.mui-tyipns > div.MuiGrid-root > a.MuiTypography-root > img
code.org/_next/static/media/powered-by-aws.f274900a.webp5.6 KiB5.4 KiB

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-5-DIV
nodeLabel: AI is reshaping the world Education must lead what comes next AI is transformi…
path: 1,HTML,1,BODY,7,MAIN,1,DIV
selector: body > main > div.cf-5c1c11cc9d6348b9402354ba1afa6063
snippet: <div style="display:flex" class="cf-5c1c11cc9d6348b9402354ba1afa6063 contentful-container" data-test-id="contentful-container">

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
value: no origins were preconnected
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
value: No additional origins are good candidates for preconnecting

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-solid-900.woff2604800.0 s253.8 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/css/fontawesome.min.css604800.0 s138.7 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-brands-400.woff2604800.0 s99.4 KiB
global.localizecdn.com/localize.js259200.0 s27.1 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/css/brands.min.css604800.0 s15.3 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/css/custom-icons.min.css604800.0 s2.6 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/css/duotone.min.css604800.0 s1.9 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/css/regular.min.css604800.0 s1.2 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/css/solid.min.css604800.0 s1.2 KiB

HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLProtocol
dsco.code.org/assets/font-awesome-pro/1764885473/css/fontawesome.min.csshttp/1.1
dsco.code.org/assets/font-awesome-pro/1764885473/css/brands.min.csshttp/1.1
dsco.code.org/assets/font-awesome-pro/1764885473/css/solid.min.csshttp/1.1
dsco.code.org/assets/font-awesome-pro/1764885473/css/regular.min.csshttp/1.1
dsco.code.org/assets/font-awesome-pro/1764885473/css/duotone.min.csshttp/1.1
dsco.code.org/assets/font-awesome-pro/1764885473/css/custom-icons.min.csshttp/1.1
dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-brands-400.woff2http/1.1
dsco.code.org/assets/font-awesome-pro/1764885473/webfonts/fa-solid-900.woff2http/1.1

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer Size
code.org/_next/static/css/3649fad98a5c4288.css3.3 KiB
code.org/_next/static/css/fc9bd2059a10c6bf.css4.8 KiB
code.org/_next/static/css/6cad3d0b054b25aa.css2.9 KiB
code.org/_next/static/css/cd681a87f39631fa.css4.7 KiB
code.org/_next/static/css/ccdbab6f669c4427.css6.6 KiB
code.org/_next/static/css/a07c7ae1d7733746.css2.2 KiB
code.org/_next/static/css/98e7c9d886edde2d.css2.2 KiB
code.org/_next/static/css/428ae77ce7d5f063.css2.4 KiB
code.org/_next/static/css/28d87e222cb9076d.css4.7 KiB
code.org/_next/static/css/4f32e6447ded6c32.css5.2 KiB
code.org/_next/static/css/a8091194558206ff.css2.6 KiB
code.org/_next/static/css/54ab74348ea3e55f.css8.5 KiB
code.org/_next/static/css/fd9143fa9538c881.css8.6 KiB
code.org/_next/static/css/5d3778b73b07efeb.css4.8 KiB
code.org/_next/static/css/39446bf7eb31383c.css936 B
code.org/_next/static/css/1ca261cdc7d789e1.css8.5 KiB
code.org/_next/static/css/f6c2429bc3b51ee0.css5.5 KiB
code.org/_next/static/css/a479fafba9d943bd.css4.8 KiB
code.org/_next/static/css/bee4ec13ee316a5e.css2.9 KiB
code.org/_next/static/css/6e1eefb1dec4ec64.css4.5 KiB
code.org/_next/static/css/a05adaee2ff82ff8.css4.3 KiB
code.org/_next/static/css/7f5925cac80368ee.css1.7 KiB
code.org/_next/static/css/94fa8b0ad645af3b.css1.9 KiB
code.org/_next/static/css/4bba0c0c0877b0da.css1.6 KiB
code.org/_next/static/css/0f0cc336d30f5fb2.css2.4 KiB
code.org/_next/static/css/b62f7b4ad22470af.css2.1 KiB
code.org/_next/static/css/3fb483857a8c9bc6.css838 B

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 264 ms
URLTime Spent
code.org/264 ms
code.org/en-US0.0 ms

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.

Diagnostics

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 110 ms 161.1 KiB
URLTransfer SizeEst Savings
www.googletagmanager.com/gtag/js?id=G-L9HT5MZ3HD178.1 KiB67.7 KiB
code.org/_next/static/chunks/326-7f1023f63cd41f9f.js67.7 KiB34.9 KiB
code.org/_next/static/chunks/5670-318ba52a6b4cab24.js57.5 KiB34.2 KiB
/_next/static/chunks/app/[brand]/[locale]/[[...paths]]/pa...65.2 KiB24.3 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 161.2 KiB
URLTransfer SizeEst Savings
dsco.code.org/assets/font-awesome-pro/1764885473/css/fontawesome.min.css138.1 KiB136.4 KiB
dsco.code.org/assets/font-awesome-pro/1764885473/css/brands.min.css14.7 KiB14.4 KiB
.mui-tyipns{background-color:var(--background-neutral-primary-inverse); … } …13.1 KiB10.3 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

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.

●Time to Interactive 2.2 s
●Layout shift culprits
●Optimize DOM size
●LCP breakdown
●Optimize viewport for mobile
●Minify CSS
●Minify JavaScript
●Avoids enormous network payloads Total size was 1,945 KiB
●User Timing marks and measures 6 user timings
●JavaScript execution time 0.7 s
●Minimizes main-thread work 1.3 s
●Avoid long main-thread tasks 4 long tasks found
●Avoid non-composited animations 32 animated elements found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 40 ms
●Server Backend Latencies 160 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 20 ms
●Avoid large layout shifts 2 layout shifts found
○INP breakdown
95

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
Learn nav.header-module__mainLinksWrapper___K-T4u > ul.header-module__mainLinks___0WyP9 > li > a
Teach nav.header-module__mainLinksWrapper___K-T4u > ul.header-module__mainLinks___0WyP9 > li > a
Districts nav.header-module__mainLinksWrapper___K-T4u > ul.header-module__mainLinks___0WyP9 > li > a
Stats nav.header-module__mainLinksWrapper___K-T4u > ul.header-module__mainLinks___0WyP9 > li.header-module__hasDisplayLogic___J-YPW > a
Donate nav.header-module__mainLinksWrapper___K-T4u > ul.header-module__mainLinks___0WyP9 > li.header-module__hasDisplayLogic___J-YPW > a
Incubator nav.header-module__mainLinksWrapper___K-T4u > ul.header-module__mainLinks___0WyP9 > li.header-module__hasDisplayLogic___J-YPW > a
About nav.header-module__mainLinksWrapper___K-T4u > ul.header-module__mainLinks___0WyP9 > li.header-module__hasDisplayLogic___J-YPW > a
New Project nav.header-module__buttonLinks___0IdUj > div > button.genericButton-module__button___-ZvEw > span
Sign In nav.header-module__buttonLinks___0IdUj > div.header-module__accountLinks___QoFXK > a.genericButton-module__button___-ZvEw > span
Create Account nav.header-module__buttonLinks___0IdUj > div.header-module__accountLinks___QoFXK > a.genericButton-module__button___-ZvEw > span
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.

Why this matters

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
New Project header.header-module__headerNavigation___GWCIp > nav.header-module__buttonLinks___0IdUj > div > button.genericButton-module__button___-ZvEw
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
○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
●`[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
●`[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 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
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements have accessible names
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○ARIA input fields have accessible names
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○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
○Elements with the `role=text` attribute do not have focusable descendents.
○ARIA toggle fields have accessible names
○ARIA `tooltip` elements have accessible names
○ARIA `treeitem` elements have accessible names
○The page contains a heading, skip link, or landmark region
○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
○Definition list items are wrapped in `<dl>` elements
○ARIA IDs are unique
○No form fields have multiple labels
○`<frame>` or `<iframe>` elements have a title
○`<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
○Links are distinguishable without relying on color.
○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>`.
○All heading elements contain content.
○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
code.org/_next/static/chunks/4445.c2d7ef35f9eae3f6.js
[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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
code.org/en-US
●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 clickjacking with XFO or CSP
●Mitigate DOM-based XSS with Trusted Types
○Redirects HTTP traffic to HTTPS
○Detected JavaScript libraries
100

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.

○Structured data is valid
●Page isn’t blocked from indexing
●Document has a `<title>` element
●Document has a meta description
●Page has successful HTTP status code
●Links have descriptive text
●Links are crawlable
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
●Document has a valid `rel=canonical`
○robots.txt is valid

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