Lighthouse Mobile

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

SCORE

GRADE

FIX

REVIEW

PASS

INFO

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.

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.

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.

Request	Cache TTL	Transfer Size
rust-lang.org/static/fonts/woff2/FiraSans-SemiBold.latin.woff2	600.0 s	19.6 KiB
rust-lang.org/static/fonts/woff2/FiraSans-ExtraBold.latin.woff2	600.0 s	19.6 KiB
rust-lang.org/static/fonts/woff2/FiraSans-Regular.latin.woff2	600.0 s	18.7 KiB
rust-lang.org/static/fonts/woff2/AlfaSlabOne-Regular.latin.woff2	600.0 s	17.2 KiB
rust-lang.org/static/styles/vendor_10880690442070639967.css	600.0 s	14.2 KiB
rust-lang.org/static/scripts/highlight.pack.js	600.0 s	9.9 KiB
rust-lang.org/static/fonts/woff2/FiraSans-Regular.cyrillic.woff2	600.0 s	9.3 KiB
rust-lang.org/static/styles/app_9373368208912545815.css	600.0 s	2.6 KiB
rust-lang.org/static/images/embedded.svg	600.0 s	2.5 KiB
rust-lang.org/static/styles/fonts_8049871103083011125.css	600.0 s	1.4 KiB
rust-lang.org/static/images/networking.svg	600.0 s	1.2 KiB
rust-lang.org/static/images/webassembly.svg	600.0 s	1.2 KiB
rust-lang.org/static/images/rust-logo-blk.svg	600.0 s	1.1 KiB
rust-lang.org/static/images/mastodon.svg	600.0 s	1.1 KiB
rust-lang.org/static/styles/a11y-dark.css	600.0 s	856 B
rust-lang.org/static/images/bluesky.svg	600.0 s	790 B
rust-lang.org/static/images/github.svg	600.0 s	788 B
rust-lang.org/static/scripts/languages.js	600.0 s	773 B
rust-lang.org/static/images/cli.svg	600.0 s	691 B
rust-lang.org/static/images/youtube.svg	600.0 s	464 B
rust-lang.org/static/scripts/init.js	600.0 s	186 B

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:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:56.924 source:map[type:text value:[unattributed]]]]

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

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.

URL	Transfer Size	Duration
rust-lang.org/static/styles/vendor_10880690442070639967.css	14.2 KiB
rust-lang.org/static/styles/a11y-dark.css	856 B	150 ms
rust-lang.org/static/styles/fonts_8049871103083011125.css	1.4 KiB
rust-lang.org/static/styles/app_9373368208912545815.css	2.6 KiB

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

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: 0.0 ms 13.7 KiB

URL	Transfer Size	Est Savings
rust-lang.org/static/styles/vendor_10880690442070639967.css	14.0 KiB	13.7 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
Bluesky `div.flex > div.flex > a > img`	rust-lang.org/static/images/bluesky.svg
terminal `div.flex-none > div.flex > div.v-top > img.mw3`	rust-lang.org/static/images/cli.svg
gear with puzzle piece elements `div.flex-none > div.flex > div.v-top > img.mw3`	rust-lang.org/static/images/webassembly.svg
a cloud with nodes `div.flex-none > div.flex > div.v-top > img.mw3`	rust-lang.org/static/images/networking.svg
an embedded device chip `div.flex-none > div.flex > div.v-top > img.mw3`	rust-lang.org/static/images/embedded.svg
github logo `div.flex > div.flex > a > img`	rust-lang.org/static/images/github.svg
youtube logo `div.flex > div.flex > a > img.pv2`	rust-lang.org/static/images/youtube.svg
Mastodon `div.flex > div.flex > a > img`	rust-lang.org/static/images/mastodon.svg
Rust Logo `nav.flex > div.brand > a.brand > img.v-mid`	rust-lang.org/static/images/rust-logo-blk.svg

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

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: 752 ms

URL	Time Spent
www.rust-lang.org/	752 ms
rust-lang.org/	0.0 ms

●Time to Interactive 2.0 s

●Layout shift culprits

●Optimize DOM size

●Font display

●Improve image delivery

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Max Potential First Input Delay 20 ms

●Minify CSS

●Minify JavaScript

●Reduce unused JavaScript

●Avoids enormous network payloads Total size was 132 KiB

●JavaScript execution time 0.0 s

●Minimizes main-thread work 0.8 s

●Avoid long main-thread tasks 2 long tasks found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 0 ms

●Server Backend Latencies 10 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 0 ms

●Avoid large layout shifts 2 layout shifts found

○INP breakdown

○LCP request discovery

○User Timing marks and measures

○Avoid non-composited animations

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
Version 1.94.1 `div.flex > div.w-30-l > p.tc > a.download-link`

Low-contrast text is difficult or impossible for many users to read. Link text that is discernible improves the experience for users with low vision. Learn how to make links distinguishable.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
File an issue! `div.w-100 > div.attribution > p > a`
previous website `div.w-100 > div.attribution > p > a`

These are opportunities to improve the legibility of your content.

○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-hidden="true"]` is not present on the document `<body>`

●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.

●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

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

○`[accesskey]` values are unique

○`[aria-*]` attributes match their roles

○`button`, `link`, and `menuitem` elements have accessible names

○ARIA attributes are used as specified for the element's role

○Deprecated ARIA roles were not used

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○`[aria-hidden="true"]` elements do not contain focusable descendents

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements use only permitted ARIA attributes

○`[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

○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

○`[aria-*]` attributes have valid values

○`[aria-*]` attributes are valid and not misspelled

○Buttons have an accessible name

○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

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Skip links are focusable.

○No element has a `[tabindex]` value greater than 0

○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.

○Elements with visible text labels have matching accessible names.

○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.

100

Best Practices

●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 browser errors logged to the console

●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

●Page has valid source maps

○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`

○robots.txt is valid

○Document has a valid `rel=canonical`