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Results for https://stackoverflow.com

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Netherlands Netherlands · Amsterdam Completed: Apr 4, 2026 16:08 UTC

Mobile 375 × 812

Screenshot of the audited page (Mobile 375×812)

Desktop 1440 × 900

Screenshot of the audited page (Desktop 1440×900)
C73

Site Health

Score: 73 / 100

Based on 8 categories, 0 sections

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

Top Priorities (5)

1

Cookie '__cflb' is missing the Secure flag

Security › Cookie Security
2

Cookie 'prov' is missing the Secure flag

Security › Cookie Security
3

Cookie '__cf_bm' has no SameSite attribute

Security › Cookie Security
4

Cookie 'prov' has no SameSite attribute

Security › Cookie Security
5

Cross-Origin-Embedder-Policy header is missing

Security › Security Headers
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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

31
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
87
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
73
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
82
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

4.17 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

13.64 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

2.77 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

7.10 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

13.77 s

Detailed Report

Audit breakdown by category with detailed findings.

31

Performance

Insights

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

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

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

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

RequestCache TTLTransfer Size
cdn.cookielaw.org/scripttemplates/202601.2.0/otBannerSdk.js86400.0 s128.4 KiB
stackoverflow.com/Content/Img/favicons-sprite32.png?v=91e30776b0a0604800.0 s275.2 KiB
stackoverflow.com/Content/Js/full-anon.en.js?v=037e97b07fca604800.0 s128.8 KiB
stackoverflow.com/Content/Shared/stacks.css?v=b2264ccf0463604800.0 s110.2 KiB
cdn.cookielaw.org/scripttemplates/202601.2.0/otGPP.js86400.0 s22.2 KiB
/cdn-cgi/challenge-platform/h/b/scripts/jsd/625261456364/...14400.0 s11.8 KiB
stackoverflow.com/Content/Sites/stackoverflow/primary.css?v=880dfade9e7f604800.0 s74.3 KiB
cdn.cookielaw.org/scripttemplates/202601.2.0/otTCF.js86400.0 s17.8 KiB
cdn.cookielaw.org/scripttemplates/otSDKStub.js86400.0 s9.1 KiB
stackoverflow.com/Content/Js/webpack-chunks/svelte.en.js?v=f773033c4e0b604800.0 s32.1 KiB
/Content/Js/third-party/npm/@stackoverflow/stacks/dist/js...604800.0 s30.5 KiB
stackoverflow.com/Content/Js/stub.en.js?v=e307fb81e738604800.0 s18.1 KiB
stackoverflow.com/Content/Js/questions/userQuestionList.en.js?v=8b4317437ce2604800.0 s16.6 KiB
/avatar/77927b8f043dd7bbb27f0018d2bd1624?s=32&d=identicon...300.0 s1.7 KiB
stackoverflow.com/Content/Js/islands/homepage-wizard.en.js?v=a74b3480697c604800.0 s16.1 KiB
www.gravatar.com/avatar/fdc1f4bd9f3118fff33a160e9efdb61e?s=32&d=identicon&r=PG300.0 s1.5 KiB
/avatar/83389645b9b5d98bffa1362da28b4711?s=32&d=identicon...300.0 s1.4 KiB
/avatar/d0fc8123a9edf2177fb66e66bf28d259?s=32&d=identicon...300.0 s1.4 KiB
stackoverflow.com/Content/Js/webpack-chunks/stacks-svelte.en.js?v=297d3b9a88f6604800.0 s12.8 KiB
stackoverflow.com/Content/Js/questions/list.en.js?v=2175cf260ad4604800.0 s12.7 KiB
/avatar/e831ce9803c96b75355e39b5371f5b70?s=32&d=identicon...300.0 s1.3 KiB
/avatar/941d88e38254d09d0d6670db673abf4b?s=32&d=identicon...300.0 s1.2 KiB
/avatar/829234be3685d327f5beed97416ec0af?s=32&d=identicon...300.0 s1.2 KiB
www.gravatar.com/avatar/20c1f68b1bb5c87878c69d5442855a28?s=32&d=identicon&r=PG300.0 s1.2 KiB
/avatar/366efa98bb157cd99284ea03b15fdca6?s=32&d=identicon...300.0 s1.2 KiB
/avatar/3f0874bd4af2ca1f3566d293d21a4961?s=32&d=identicon...300.0 s1.2 KiB
lngtd.com/stackoverflow.js900.0 s1.2 KiB
/avatar/9875608b463550ab1a13be2f2c30a9b3?s=32&d=identicon...300.0 s1.0 KiB
www.gravatar.com/avatar/4288427122ae357b092954b12d139311?s=32&d=identicon&r=PG300.0 s1.0 KiB
/avatar/c4c291308f93584ca1d125f2b9c0ccfa?s=32&d=identicon...300.0 s995 B
stackoverflow.com/Content/Js/webpack-chunks/9366.en.js?v=c8d4e4e64bf3604800.0 s8.5 KiB
stackoverflow.com/Content/Js/islands/signup-modal.en.js?v=f64ec881ea96604800.0 s8.4 KiB
/Content/Js/webpack-chunks/stacks-svelte-labs.en.js?v=b9c...604800.0 s7.7 KiB
cdn.cookielaw.org/scripttemplates/gpp.stub.js86400.0 s1.9 KiB
stackoverflow.com/Content/Js/webpack-chunks/7663.en.js?v=c67f16729ba4604800.0 s7.4 KiB
stackoverflow.com/Content/Js/webpack-chunks/9001.en.js?v=3a153d433746604800.0 s5.2 KiB
stackoverflow.com/Content/Js/webpack-chunks/8339.en.js?v=4cb8dd34a7f9604800.0 s4.9 KiB
stackoverflow.com/Content/Js/topbar/top-bar-events.en.js?v=9f5a4d15c5cd604800.0 s4.8 KiB
stackoverflow.com/Content/Shared/Channels/channels.css?v=d431b1be5a03604800.0 s4.7 KiB
stackoverflow.com/px.js?ch=214400.0 s547 B
stackoverflow.com/px.js?ch=114400.0 s369 B
stackoverflow.com/Content/Js/google-analytics.en.js?v=48615a9a9bc4604800.0 s2.4 KiB
stackoverflow.com/Content/Js/webpack-chunks/3696.en.js?v=7ef09fb6562b604800.0 s2.2 KiB
stackoverflow.com/Content/Js/islands/one-tap.en.js?v=102f0378a2cf604800.0 s1.7 KiB
stackoverflow.com/Content/Js/webpack-chunks/620.en.js?v=a432091814d8604800.0 s1.6 KiB
/Content/Sites/stackoverflow/Img/subcommunities/ci-cd.svg...604800.0 s1.5 KiB
stackoverflow.com/Content/Js/sprinkles/left-nav-events.en.js?v=2ac13fd60bf6604800.0 s1.1 KiB
stackoverflow.com/Content/Js/sprinkles/cookie-consent.en.js?v=7ee6963139c5604800.0 s1.1 KiB
/Content/Sites/stackoverflow/Img/subcommunities/google-cl...604800.0 s1.0 KiB
/Content/Sites/stackoverflow/Img/subcommunities/php.svg?v...604800.0 s1004 B
/Content/Sites/stackoverflow/Img/subcommunities/mobile-de...604800.0 s817 B
stackoverflow.com/Content/Js/webpack-chunks/2458.en.js?v=33cc3da05f78604800.0 s796 B
stackoverflow.com/Content/Js/webpack-chunks/5102.en.js?v=77170ebd8b1b604800.0 s728 B
stackoverflow.com/Content/Sites/stackoverflow/Img/icon-48.png?v=6452e6a98212604800.0 s457 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

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.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:17.149 source:map[column:27323 line:2 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:1.391 source:map[column:50335 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]] map[reflowTime:0.655 source:map[column:50393 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]] map[reflowTime:0.521 source:map[column:50457 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]] map[reflowTime:5.09 source:map[column:49637 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]] map[reflowTime:21.205 source:map[column:49615 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]] map[reflowTime:0.812 source:map[column:51395 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]] map[reflowTime:0.82 source:map[column:79427 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]] map[reflowTime:0.35 source:map[column:5984 line:0 type:source-location url:https://stackoverflow.com/Content/Js/questions/userQuestionList.en.js?v=8b4317437ce2 urlProvider:network]] map[reflowTime:0.456 source:map[column:83946 line:1 type:source-location url:https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js urlProvider:network]]]

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.

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

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

URLResource SizeEst Savings
div#hot-network-questions > ul > li.js-hidden > div.favicon div#hot-network-questions > ul > li.js-hidden > div.favicon
stackoverflow.com/Content/Img/favicons-sprite32.png?v=91e30776b0a0274.8 KiB200.7 KiB

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

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.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Estimated savings: 783 ms

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.

TTI

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.

Estimated savings: 720 ms 170.9 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.

URLTotal CPU TimeScript EvaluationScript Parse
stackoverflow.com/questions1.2 s106 ms28 ms
Unattributable974 ms19 ms0.0 ms
cdn.cookielaw.org/scripttemplates/202601.2.0/otGPP.js936 ms825 ms37 ms
stackoverflow.com/Content/Js/islands/homepage-wizard.en.js?v=a74b3480697c614 ms483 ms7.5 ms
www.googletagmanager.com/gtag/js?id=G-WCZ03SZFCQ468 ms383 ms81 ms
s.lngtdv.com/stackoverflow/default.1775148653.js449 ms370 ms59 ms
stackoverflow.com/cdn-cgi/challenge-platform/scripts/jsd/main.js447 ms415 ms4.6 ms
/pagead/managed/js/gpt/m202604010101/pubads_impl.js?cb=31...396 ms293 ms96 ms
stackoverflow.com/Content/Js/stub.en.js?v=e307fb81e738328 ms191 ms8.0 ms
cdn.cookielaw.org/scripttemplates/202601.2.0/otBannerSdk.js318 ms140 ms101 ms
s.lngtdv.com/prebid/stackoverflow/prebid10.27.0.1774971607.min.js308 ms213 ms93 ms
stackoverflow.com/Content/Js/islands/signup-modal.en.js?v=f64ec881ea96250 ms214 ms3.4 ms
stackoverflow.com/Content/Js/full-anon.en.js?v=037e97b07fca246 ms150 ms80 ms
stackoverflow.com/Content/Js/islands/one-tap.en.js?v=102f0378a2cf147 ms75 ms1.0 ms
pagead2.googlesyndication.com/tag/js/gpt.js138 ms116 ms21 ms
ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js129 ms108 ms16 ms
/Content/Js/third-party/npm/@stackoverflow/stacks/dist/js...109 ms84 ms20 ms
cdn.cookielaw.org/scripttemplates/otSDKStub.js109 ms92 ms4.9 ms
accounts.google.com/gsi/client88 ms41 ms46 ms
stackoverflow.com/Content/Js/webpack-chunks/9001.en.js?v=3a153d43374683 ms28 ms1.9 ms
cdn.cookielaw.org/scripttemplates/gpp.stub.js69 ms60 ms2.1 ms
stackoverflow.com/Content/Js/webpack-chunks/svelte.en.js?v=f773033c4e0b65 ms18 ms45 ms
stackoverflow.com/Content/Js/questions/userQuestionList.en.js?v=8b4317437ce257 ms13 ms7.1 ms
stackoverflow.com/Content/Js/webpack-chunks/7663.en.js?v=c67f16729ba450 ms33 ms2.8 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

CategoryTime Spent
Script Evaluation4.5 s
Style & Layout1.1 s
Other1.1 s
Script Parsing & Compilation832 ms
Parse HTML & CSS328 ms
Garbage Collection158 ms
Rendering106 ms

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

Layout shift culprits
Optimize DOM size
Font display
LCP breakdown
Modern HTTP
Optimize viewport for mobile
Minify CSS
Minify JavaScript
Avoids enormous network payloads Total size was 1,980 KiB
User Timing marks and measures 5 user timings
Avoid long main-thread tasks 20 long tasks found
Image elements have explicit `width` and `height`
Page didn't prevent back/forward cache restoration
Network Requests
Network Round Trip Times 30 ms
Server Backend Latencies 30 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Initial server response time was short Root document took 140 ms
INP breakdown
LCP request discovery
Avoid non-composited animations
Avoid large layout shifts
87

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.

Failing Elements
15 div#content > div#mainbar > div.s-pagination > a.s-pagination--item

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.

Failing Elements
Why is Spring Boot still used in large-scale systems despite newer backend fram… div.bb > div#question-summary-79920167 > div.s-post-summary--content > h3.s-post-summary--content-title
Hot Network Questions div#content > div#sidebar > div#hot-network-questions > h4

These are opportunities to improve keyboard navigation in your application.

Names and labels

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Failing Elements
body.questions-page > header.s-topbar > div.s-topbar--container > a.s-topbar--menu-btn body.questions-page > header.s-topbar > div.s-topbar--container > a.s-topbar--menu-btn
div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed
div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed
div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed

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.

Best practices

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Failing Elements
BUSINESS nav.site-footer--nav > div.site-footer--col > h5.-title > a.js-gps-track
Stack Internal div.site-footer--col > ul.-list > li > a.js-gps-track
Technology div > ul.-list > li > a.-link
Business div > ul.-list > li > a.-link

These items highlight common accessibility best practices.

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.
ARIA attributes are used as specified for the element's role
Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
`[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
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
Document has a main landmark.
Deprecated ARIA roles were not used
ARIA IDs are unique
Uses ARIA roles only on compatible elements
Identical links have the same purpose.
Elements with visible text labels have matching accessible names.
`[accesskey]` values are unique
`button`, `link`, and `menuitem` elements 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
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
Select elements have associated label elements.
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.
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.
73

Best Practices

User Experience

Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.

URLDisplayed sizeActual sizeExpected size
site logo div.s-modal--dialog > h1#signup-modal-title > div.s-modal--header > img.h48
stackoverflow.com/Content/Sites/stackoverflow/Img/icon-48.png?v=6452e6a9821248 x 4848 x 4872 x 72

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Deprecation / WarningSource
SharedStorage
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.
Fledge

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

SourceDescription
Not signed in with the identity provider.
Uses HTTPS
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
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 DOM-based XSS with Trusted Types
Detected JavaScript libraries
Page has valid source maps
Redirects HTTP traffic to HTTPS
Mitigate clickjacking with XFO or CSP
82

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

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

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

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
Page has successful HTTP status code
Links are crawlable
Image elements have `[alt]` attributes
Document has a valid `hreflang`
robots.txt is valid
Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

72
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
92
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
82
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

712 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

2.61 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

286 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.001

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.56 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

2.61 s

Detailed Report

Audit breakdown by category with detailed findings.

72

Performance

Insights

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

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

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

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

RequestCache TTLTransfer Size
cdn.cookielaw.org/scripttemplates/202601.2.0/otBannerSdk.js86400.0 s128.4 KiB
stackoverflow.com/Content/Js/full-anon.en.js?v=037e97b07fca604800.0 s128.8 KiB
stackoverflow.com/Content/Shared/stacks.css?v=b2264ccf0463604800.0 s110.2 KiB
cdn.cookielaw.org/scripttemplates/202601.2.0/otGPP.js86400.0 s22.2 KiB
stackoverflow.com/Content/Img/favicons-sprite16.png?v=7c49858b1c47604800.0 s87.7 KiB
/cdn-cgi/challenge-platform/h/b/scripts/jsd/625261456364/...14400.0 s11.7 KiB
stackoverflow.com/Content/Sites/stackoverflow/primary.css?v=880dfade9e7f604800.0 s74.4 KiB
cdn.cookielaw.org/scripttemplates/202601.2.0/otTCF.js86400.0 s17.8 KiB
cdn.cookielaw.org/scripttemplates/otSDKStub.js86400.0 s8.8 KiB
stackoverflow.com/Content/Js/webpack-chunks/svelte.en.js?v=f773033c4e0b604800.0 s32.2 KiB
/Content/Js/third-party/npm/@stackoverflow/stacks/dist/js...604800.0 s30.5 KiB
stackoverflow.com/Content/Js/stub.en.js?v=e307fb81e738604800.0 s18.0 KiB
stackoverflow.com/Content/Js/questions/userQuestionList.en.js?v=8b4317437ce2604800.0 s16.6 KiB
/avatar/77927b8f043dd7bbb27f0018d2bd1624?s=32&d=identicon...300.0 s1.7 KiB
stackoverflow.com/Content/Js/islands/homepage-wizard.en.js?v=a74b3480697c604800.0 s16.1 KiB
www.gravatar.com/avatar/fdc1f4bd9f3118fff33a160e9efdb61e?s=32&d=identicon&r=PG300.0 s1.5 KiB
/avatar/83389645b9b5d98bffa1362da28b4711?s=32&d=identicon...300.0 s1.4 KiB
/avatar/d0fc8123a9edf2177fb66e66bf28d259?s=32&d=identicon...300.0 s1.4 KiB
stackoverflow.com/Content/Js/webpack-chunks/stacks-svelte.en.js?v=297d3b9a88f6604800.0 s12.8 KiB
stackoverflow.com/Content/Js/questions/list.en.js?v=2175cf260ad4604800.0 s12.7 KiB
/avatar/e831ce9803c96b75355e39b5371f5b70?s=32&d=identicon...300.0 s1.3 KiB
/avatar/941d88e38254d09d0d6670db673abf4b?s=32&d=identicon...300.0 s1.2 KiB
/avatar/829234be3685d327f5beed97416ec0af?s=32&d=identicon...300.0 s1.2 KiB
www.gravatar.com/avatar/20c1f68b1bb5c87878c69d5442855a28?s=32&d=identicon&r=PG300.0 s1.2 KiB
/avatar/366efa98bb157cd99284ea03b15fdca6?s=32&d=identicon...300.0 s1.2 KiB
/avatar/3f0874bd4af2ca1f3566d293d21a4961?s=32&d=identicon...300.0 s1.2 KiB
lngtd.com/stackoverflow.js900.0 s1.2 KiB
/avatar/9875608b463550ab1a13be2f2c30a9b3?s=32&d=identicon...300.0 s1.0 KiB
www.gravatar.com/avatar/4288427122ae357b092954b12d139311?s=32&d=identicon&r=PG300.0 s1.0 KiB
/avatar/c4c291308f93584ca1d125f2b9c0ccfa?s=32&d=identicon...300.0 s995 B
cdn.cookielaw.org/scripttemplates/gpp.stub.js86400.0 s2.1 KiB
stackoverflow.com/Content/Js/webpack-chunks/9366.en.js?v=c8d4e4e64bf3604800.0 s8.5 KiB
stackoverflow.com/Content/Js/islands/signup-modal.en.js?v=f64ec881ea96604800.0 s8.4 KiB
/Content/Js/webpack-chunks/stacks-svelte-labs.en.js?v=b9c...604800.0 s7.7 KiB
stackoverflow.com/Content/Js/webpack-chunks/7663.en.js?v=c67f16729ba4604800.0 s7.4 KiB
stackoverflow.com/Content/Js/webpack-chunks/9001.en.js?v=3a153d433746604800.0 s5.2 KiB
stackoverflow.com/Content/Js/webpack-chunks/8339.en.js?v=4cb8dd34a7f9604800.0 s4.9 KiB
stackoverflow.com/Content/Js/topbar/top-bar-events.en.js?v=9f5a4d15c5cd604800.0 s4.8 KiB
stackoverflow.com/Content/Shared/Channels/channels.css?v=d431b1be5a03604800.0 s4.6 KiB
stackoverflow.com/px.js?ch=114400.0 s525 B
stackoverflow.com/px.js?ch=214400.0 s369 B
stackoverflow.com/Content/Js/google-analytics.en.js?v=48615a9a9bc4604800.0 s2.4 KiB
/Content/Sites/stackoverflow/Img/subcommunities/aws.svg?v...604800.0 s2.3 KiB
stackoverflow.com/Content/Js/webpack-chunks/3696.en.js?v=7ef09fb6562b604800.0 s2.1 KiB
stackoverflow.com/Content/Js/islands/one-tap.en.js?v=102f0378a2cf604800.0 s1.7 KiB
stackoverflow.com/Content/Js/webpack-chunks/620.en.js?v=a432091814d8604800.0 s1.6 KiB
/Content/Sites/stackoverflow/Img/subcommunities/ci-cd.svg...604800.0 s1.4 KiB
stackoverflow.com/Content/Js/sprinkles/left-nav-events.en.js?v=2ac13fd60bf6604800.0 s1.1 KiB
/Content/Sites/stackoverflow/Img/subcommunities/php.svg?v...604800.0 s1003 B
stackoverflow.com/Content/Js/sprinkles/cookie-consent.en.js?v=7ee6963139c5604800.0 s942 B
stackoverflow.com/Content/Js/webpack-chunks/2458.en.js?v=33cc3da05f78604800.0 s796 B
/Content/Sites/stackoverflow/Img/subcommunities/mobile-de...604800.0 s731 B
stackoverflow.com/Content/Js/webpack-chunks/5102.en.js?v=77170ebd8b1b604800.0 s728 B
stackoverflow.com/Content/Sites/stackoverflow/Img/icon-48.png?v=6452e6a98212604800.0 s481 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

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.

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:45.973 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

URLResource SizeEst Savings
div#hot-network-questions > ul > li.js-hidden > div.favicon div#hot-network-questions > ul > li.js-hidden > div.favicon
stackoverflow.com/Content/Img/favicons-sprite16.png?v=7c49858b1c4787.4 KiB68.8 KiB

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.

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

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.

Estimated savings: 225 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.

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.

TTI

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.

Estimated savings: 130 ms 171.3 KiB

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

Layout shift culprits
Optimize DOM size
Font display
LCP breakdown
Modern HTTP
Optimize viewport for mobile
Minify CSS
Minify JavaScript
Avoids enormous network payloads Total size was 1,621 KiB
User Timing marks and measures 5 user timings
JavaScript execution time 1.0 s
Minimizes main-thread work 2.0 s
Avoid long main-thread tasks 7 long tasks found
Image elements have explicit `width` and `height`
Page didn't prevent back/forward cache restoration
Network Requests
Network Round Trip Times 20 ms
Server Backend Latencies 40 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Initial server response time was short Root document took 140 ms
Avoid large layout shifts 1 layout shift found
INP breakdown
LCP request discovery
Avoid non-composited animations
92

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.

Failing Elements
15 div#content > div#mainbar > div.s-pagination > a.s-pagination--item

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.

Failing Elements
Why is Spring Boot still used in large-scale systems despite newer backend fram… div.bb > div#question-summary-79920167 > div.s-post-summary--content > h3.s-post-summary--content-title
Hot Network Questions div#content > div#sidebar > div#hot-network-questions > h4

These are opportunities to improve keyboard navigation in your application.

Names and labels

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Failing Elements
div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed
div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed
div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed div.s-post-summary--content > div.s-post-summary--meta > div.s-post-summary--meta-tags > a.themed

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.

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
Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
`[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 are distinguishable without relying on color.
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
ARIA IDs are unique
Uses ARIA roles only on compatible elements
Identical links have the same purpose.
Elements with visible text labels have matching accessible names.
`[accesskey]` values are unique
`button`, `link`, and `menuitem` elements 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
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
The document does not use `<meta http-equiv="refresh">`
`<object>` elements have alternate text
Select elements have associated label elements.
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.
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.
77

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Deprecation / WarningSource
SharedStorage
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.
Fledge

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

SourceDescription
Not signed in with the identity provider.
Uses HTTPS
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 DOM-based XSS with Trusted Types
Detected JavaScript libraries
Page has valid source maps
Redirects HTTP traffic to HTTPS
Mitigate clickjacking with XFO or CSP
82

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

Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.

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

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
Page has successful HTTP status code
Links are crawlable
Image elements have `[alt]` attributes
Document has a valid `hreflang`
robots.txt is valid
Document has a valid `rel=canonical`

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