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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.

99

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.

RequestCache TTLTransfer Size
dartpad.dev/codemirror/codemirror.js3600.0 s105.3 KiB
www.google-analytics.com/analytics.js7200.0 s20.9 KiB
www.google-analytics.com/analytics.js7200.0 s20.9 KiB
dart.dev/assets/dash/svg/1-1-async-await.svg28800.0 s15.1 KiB
dart.dev/assets/dash/2x/supported-by-google.png28800.0 s14.0 KiB
dart.dev/assets/css/main.css?hash=C7aJidT1dEMd28800.0 s13.2 KiB
dart.dev/assets/dash/svg/2-1-hot-reload-iterative-changes.svg28800.0 s12.6 KiB
dartpad.dev/main.dart.mjs3600.0 s8.2 KiB
dart.dev/assets/dash/svg/3-1-aot-compile.svg28800.0 s7.2 KiB
dart.dev/main.client.mjs3600.0 s5.3 KiB
dart.dev/assets/dash/2x/client-optimized-light-op1.png28800.0 s6.1 KiB
dart.dev/assets/dash/2x/multiplatform-performance-light-op1.png28800.0 s5.5 KiB
dart.dev/assets/dash/2x/productive-dev-light-op1.png28800.0 s4.1 KiB
dartpad.dev/codemirror/css/codemirror.css3600.0 s3.0 KiB
dart.dev/assets/img/logo/logo-white-text.svg28800.0 s2.1 KiB
dartpad.dev/ga.js3600.0 s788 B
dartpad.dev/styles/cm-dartpad-dark.css3600.0 s708 B
dartpad.dev/styles/cm-dartpad-light.css3600.0 s702 B
dart.dev/main.client.dart.js28800.0 s901 B
dart.dev/assets/img/logo/dart-192.svg28800.0 s855 B
dartpad.dev/codemirror/codemirror.css3600.0 s270 B

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
/s/materialsymbolsoutlined/v323/kJF4BvYX7BgnkSrUwT8OhrdQw...140 ms

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
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

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 SizeDuration
fonts.googleapis.com/css2?family=Google+Sans:wght@400;500;700&display=swap2.3 KiB290 ms
fonts.googleapis.com/css2?family=Google+Sans+Text:wght@400;500;700&display=swap2.4 KiB
/css2?family=Material+Symbols+Outlined:opsz,wght,FILL,GRA...501 B
fonts.googleapis.com/css2?family=Google+Sans+Mono:wght@400;500;700&display=swap1.5 KiB65 ms
dart.dev/assets/css/main.css?hash=C7aJidT1dEMd13.2 KiB

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
Supported by Google main#page-content > section.content > section#site-content-title > img.made-by
dart.dev/assets/dash/2x/supported-by-google.png14.4 KiB13.1 KiB

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

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: 0.0 ms 134.6 KiB
URLTransfer SizeEst Savings
www.googletagmanager.com/gtm.js?id=GTM-5VSZM5J132.1 KiB72.8 KiB
www.googletagmanager.com/gtag/js?id=G-X5H2ZXSYH5&cx=c&_slc=1149.7 KiB61.8 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer Size
/flutter-canvaskit/3ff83f39d2fe9c228f4fa16709392c27ef1d7d...1.2 MiB
dartpad.dev/main.dart.wasm790.6 KiB
/s/materialsymbolsoutlined/v323/kJF4BvYX7BgnkSrUwT8OhrdQw...439.8 KiB
dart.dev/main.client.wasm163.7 KiB
www.googletagmanager.com/gtag/js?id=G-X5H2ZXSYH5&cx=c&_slc=1149.8 KiB
www.googletagmanager.com/gtm.js?id=GTM-5VSZM5J132.5 KiB
dartpad.dev/codemirror/codemirror.js105.3 KiB
fonts.gstatic.com/s/roboto/v32/KFOmCnqEu92Fr1Me4GZLCzYlKw.woff262.0 KiB
dartpad.dev/assets/assets/RobotoMono-Bold.ttf47.9 KiB
dartpad.dev/assets/assets/RobotoMono-Regular.ttf47.4 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
Dart footer#page-footer > div.footer-section > a.brand > img
dart.dev/assets/img/logo/logo-white-text.svg
Dart logo header#site-header > nav.navbar > a#site-primary-logo > img
dart.dev/assets/img/logo/dart-192.svg
Supported by Google main#page-content > section.content > section#site-content-title > img.made-by
dart.dev/assets/dash/2x/supported-by-google.png
Async await functions div.dart-dash-details > section.dash-row > div.content-image > img.galleryOne
dart.dev/assets/dash/svg/1-1-async-await.svg
Compiling dart file div.dart-dash-details > section.dash-row > div.content-image > img.galleryThree
dart.dev/assets/dash/svg/3-1-aot-compile.svg
Hot reload your changes div.dart-dash-details > section.dash-row > div.content-image > img.galleryTwo
dart.dev/assets/dash/svg/2-1-hot-reload-iterative-changes.svg

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

●Time to Interactive 1.9 s
●Layout shift culprits
●Document request latency
●Optimize DOM size
●Forced reflow
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Max Potential First Input Delay 60 ms
●Minify CSS
●Minify JavaScript
●Reduce unused CSS
●User Timing marks and measures 5 user timings
●JavaScript execution time 0.1 s
●Minimizes main-thread work 0.4 s
●Avoid long main-thread tasks 1 long task found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 30 ms
●Server Backend Latencies 200 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Avoid multiple page redirects
●Initial server response time was short Root document took 0 ms
●Avoid large layout shifts 2 layout shifts found
○INP breakdown
○LCP request discovery
○Avoid non-composited animations
93

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.

Names and labels

Screen reader users rely on frame titles to describe the contents of frames. Learn more about frame titles.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
section.dash-dartpad-row > div.dash-dartpad > div#dartpad-host > iframe section.dash-dartpad-row > div.dash-dartpad > div#dartpad-host > iframe

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Navigation

A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. Learn more about the `tabindex` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Skip to main content body.homepage > a#skip-to-main

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
Dart body.homepage > header#site-header > nav.navbar > a#site-primary-logo
○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
●Form elements have associated labels
●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
●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
●Background and foreground colors have a sufficient contrast ratio
●Document has a `<title>` element
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links are distinguishable without relying on color.
●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
●Skip links are focusable.
●Document has a main landmark.
●Deprecated ARIA roles were not used
●Identical links have the same purpose.
○`[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
○`<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
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○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.
○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

Issues logged to the `Issues` panel in Chrome Devtools indicate unresolved problems. They can come from network request failures, insufficient security controls, and other browser concerns. Open up the Issues panel in Chrome DevTools for more details on each issue.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Issue type
Content security policy
●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
●Ensure CSP is effective against XSS attacks
●Use a strong HSTS policy
●Ensure proper origin isolation with COOP
●Mitigate DOM-based XSS with Trusted Types
●Page has valid source maps
○Redirects HTTP traffic to HTTPS
○Mitigate clickjacking with XFO or CSP
○Detected JavaScript libraries
92

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.

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destinationLink Text
policies.google.com/technologies/cookiesLearn more
blog.dart.dev/announcing-dart-3-11-b6529be4203aLearn more

Format your HTML in a way that enables crawlers to better understand your app’s content.

○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 are crawlable
●robots.txt is valid
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
○Document has a valid `rel=canonical`

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