Page summary

https://en.wikipedia.org/wiki/Main_Page

Tested 2026-05-26 04:21:53 using Firefox 150.0.2 (runtime settings)

SummaryWaterfall MetricsVideoFilmstrip CoachPageXrayCPU
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Summary

LCP1.610 s
Coach88
Loading & responsiveness (median)
TTFB
406 ms
First Paint
857 ms
Fully Loaded
1.717 s
Page weight & requests
Total transfer size
649.7 KB
Requests
39
Visual progress
First Visual Change
900 ms
Speed Index
997 ms
Visual Complete 85%
900 ms
Visual Complete 99%
1.633 s
Last Visual Change
2.633 s
Screenshot of run 3

Timings Summary

Metricminmedianmeanmax
Visual Metrics
FirstVisualChange867 ms900 ms887 ms900 ms
LastVisualChange2.600 s2.633 s2.647 s2.700 s
SpeedIndex964 ms997 ms986 ms1.002 s
LargestImage1.467 s1.500 s1.507 s1.533 s
Heading1.467 s1.500 s1.507 s1.533 s
LargestContentfulPaint1.600 s1.633 s1.633 s1.667 s
LastMeaningfulPaint1.600 s1.633 s1.633 s1.667 s
VisualReadiness1.733 s1.733 s1.760 s1.800 s
VisualComplete85867 ms900 ms887 ms900 ms
VisualComplete951.600 s1.633 s1.633 s1.667 s
VisualComplete991.600 s1.633 s1.640 s1.700 s
Google Web Vitals
Time To First Byte (TTFB)406 ms406 ms407 ms411 ms
Largest Contentful Paint (LCP)1.593 s1.610 s1.624 s1.661 s
More metrics
firstPaint820 ms857 ms845 ms867 ms
loadEventEnd1.590 s1.612 s1.622 s1.670 s
User Timing
mwStartup813 ms841 ms832 ms842 ms
mwCentralNoticeBanner1.427 s1.460 s1.463 s1.508 s
Waterfall | Download HAR | 

Waterfall

Run 3 SpeedIndex median

First paintFCPLCPDOMContentLoadedDOM interactiveLoadRender-blockingRedirectError

Video

Run 3 · median
Download video

Filmstrip

20 frames

Use --filmstrip.showAll to show all filmstrips.

0 s
0.9 smwStartup 841 msFirst Contentful Paint 868 msDOM Content Loaded Time 870 msFirst Visual Change 900 msVisual Complete 85% 900 ms
1 s
1.1 s
1.2 s
1.3 s
1.4 s
1.5 s
1.6 smwCentralNoticeBanner 1.508 sLargest Image 1.533 sHeading 1.533 s
1.7 sLCP <DIV> 1.661 sVisual Complete 95% 1.667 sPage Load Time 1.670 sVisual Complete 99% 1.700 s
1.8 sFully Loaded 1.775 s
1.9 s
2 s
2.1 s
2.2 s
2.3 s
2.4 s
2.5 s
2.6 s
2.7 sLast Visual Change 2.700 s
Performance advice | Best practice advice | Privacy advice | Page info | Technologies | 

Coach

The coach helps you find performance problems on your web page using web performance best practice rules. And gives you advice on privacy and best practices. Tested using Coach-core version 9.2.1.

Performance advice

88
9 warnings2 info
warn(0)Serve images in modern formats (AVIF, WebP)modernImageFormats

The page ships 18 images (out of 18) in JPEG/PNG/GIF without a modern alternative. Wrap them in a <picture> with a <source type="image/avif"> or "image/webp" before the legacy <img>, or serve modern formats from your image pipeline directly. AVIF and WebP usually deliver 25–50% smaller files at the same quality.

AVIF and WebP routinely deliver 25–50% smaller files than JPEG and PNG at the same perceived quality, and every browser version still under support understands at least one of them. Ship modern formats either through a <picture> element with <source type="image/avif"> / "image/webp" entries in front of the legacy <img>, or directly from a content-negotiating image pipeline that returns AVIF / WebP when the client accepts it. https://web.dev/articles/serve-images-webp

Offenders
warn(0)Avoid extra requests by setting cache headerscacheHeaders

The page has 23 requests that are missing a cache time. Configure a cache time so the browser doesn't need to download them every time. It will save 238.8 kB the next access.

The easiest way to make your page fast is to avoid doing requests to the server. Setting a cache header on your server response will tell the browser that it doesn't need to download the asset again during the configured cache time! Always try to set a cache time if the content doesn't change for every request.

Offenders
warn(14)Lazy-load below-the-fold imageslazyLoadingImages

The page has 12 below-the-fold images without loading="lazy". Add loading="lazy" so the browser defers downloading and decoding them until the user scrolls them into view.

Adding loading="lazy" to an <img> tells the browser not to download or decode it until it is close to the viewport. For images that the user may never see (deep in the page, behind a tab, in a footer carousel), this saves bandwidth and main-thread time during initial render. The LCP image and any image in the initial viewport should NOT be lazy-loaded — that delays the first paint. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#loading

Offenders
warn(50)Don't scale images in the browseravoidScalingImages

The page has 5 images that are scaled more than 100 pixels. It would be better if those images are sent so the browser don't need to scale them.

It's easy to scale images in the browser and make sure they look good in different devices, however that is bad for performance! Scaling images in the browser takes extra CPU time and will hurt performance on mobile. And the user will download extra kilobytes (sometimes megabytes) of data that could be avoided. Don't do that, make sure you create multiple version of the same image server-side and serve the appropriate one.

Offenders
warn(50)Total JavaScript size shouldn't be too bigjavascriptSize
infoAdd decoding="async" to non-critical imagesdecodingAsync

The page has 6 images (out of 23) without a decoding hint. Add decoding="async" to non-critical images so the browser can decode them off the main thread.

Setting decoding="async" on an <img> tells the browser it can decode the image off the main thread, which keeps the page responsive to user interactions while images are being processed. The default ("auto") leaves the choice to the browser. https://developer.mozilla.org/en-US/docs/Web/HTML/Element/img#decoding

Offenders
warn(90)Avoid doing redirectsassetsRedirects

The page has 1 redirect. 1 of the redirects are from the base domain, please fix them!

A redirect is one extra step for the user to download the asset. Avoid that if you want to be fast. Redirects are even more of a showstopper on mobile.

Offenders
infoLong cache headers is goodcacheHeadersLong

The page has 10 requests that have a shorter cache time than one year (but still a cache time).

Setting a cache header is good. Setting a long cache header (a year) is even better because the asset will stay in the browser cache across visits. For content-hashed URLs (e.g. app.4af2.css) you can safely use Cache-Control: max-age=31536000, immutable. For unversioned URLs that may change, use a revalidating strategy instead.

Offenders
warn(90)Don't use private headers on static contentprivateAssets

The page has 2 requests with private headers. The main page has a private header. It could be right in some cases where the user can be logged in and served specific content. But if your asset is static it should never be private. Make sure that the assets really should be private and only used by one user. Otherwise, make it cacheable for everyone.

If you set private headers on content, that means that the content are specific for that user. Static content should be able to be cached and used by everyone. Avoid setting the cache header to private.

Offenders
warn(95)Avoid slowing down the critical rendering pathavoidRenderBlocking

The style https://en.wikipedia.org/w/load.php?lang=en&modules=ext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediamessages.styles%7Cmediawiki.skins.legacy%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022 is larger than the magic number TCP window size 14.5 kB. Make the file smaller and the page will render faster. The page has 1 render blocking CSS request and 0 blocking JavaScript request inside of head.

The critical rendering path is what the browser needs to do to start rendering the page. Every file requested inside of the head element will postpone the rendering of the page, because the browser need to do the request. Avoid loading JavaScript synchronously inside of the head (you should not need JavaScript to render the page), request files from the same domain as the main document (to avoid DNS lookups) and inline CSS for really fast rendering and a short rendering path.

Offenders
warn(95)Inline CSS for faster first renderinlineCss

The page has both inline CSS and CSS requests even though it uses a HTTP/2-ish connection. If you have many users on slow connections, it can be better to only inline the CSS. Run your own tests and check the waterfall graph to see what happens.

In the early days of the Internet, inlining CSS was one of the ugliest things you can do. That has changed if you want your page to start rendering fast for your user. Always inline the critical CSS when you use HTTP/1 and HTTP/2 (avoid doing CSS requests that block rendering) and lazy load and cache the rest of the CSS. It is a little more complicated when using HTTP/2. Does your server support HTTP push? Then maybe that can help. Do you have a lot of users on a slow connection and are serving large chunks of HTML? Then it could be better to use the inline technique, becasue some servers always prioritize HTML content over CSS so the user needs to download the HTML first, before the CSS is downloaded.

Best practice advice

67
1 error1 warning3 info
error(0)Cumulative Layout ShiftcumulativeLayoutShift

Layout Shift is not supported in this browser

Cumulative Layout Shift measures the sum total of all individual layout shift scores for unexpected layout shift that occur. The metric is measuring visual stability by quantify how often users experience unexpected layout shifts. It is one of Google Web Vitals.

infoMeta descriptionmetaDescription

The page is missing a meta description.

Use a page description to make the page more relevant to search engines.

infoAvoid unnecessary headersunnecessaryHeaders

There are 15 responses that sets both a max-age and expires header. There are 39 responses that sets a server header.

Do not send headers that you don't need. We look for p3p, cache-control and max-age, pragma, server and x-frame-options headers. Have a look at Andrew Betts - Headers for Hackers talk as a guide https://www.youtube.com/watch?v=k92ZbrY815c or read https://www.fastly.com/blog/headers-we-dont-want.

Offenders
warn(50)Set a sensible viewport meta tagviewport

The viewport meta tag does not contain width=device-width, the browser may use a desktop-width fallback.

The viewport meta tag tells the browser how to lay out the page on small screens. Without it (or without width=device-width) the page is rendered at a desktop fallback width and scaled down, which makes text unreadable on mobile. Disabling zoom (user-scalable=no, maximum-scale<=1) is also an accessibility regression. https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag

infoDo not send too long headerslongHeaders

https://en.wikipedia.org/wiki/Main_Page has a header content-security-policy that is 4501 characters long. https://en.wikipedia...ia.org/w/load.php has a header sourcemap that is 1082 characters long.

Do not send response headers that are too long.

Offenders

Privacy advice

80
4 warnings2 info
infoSet a Cross-Origin-Embedder-Policy header so cross-origin subresources opt in to being embedded.crossOriginEmbedderPolicyHeader

Set a Cross-Origin-Embedder-Policy header (typically require-corp or credentialless) on the document response to control cross-origin embedding.

Cross-Origin-Embedder-Policy (COEP) makes the page refuse to load cross-origin subresources unless they explicitly opt in via CORP or CORS. Together with Cross-Origin-Opener-Policy it puts the page in a cross-origin isolated context, which mitigates cross-window side-channel attacks (Spectre) and unlocks high-resolution timers and SharedArrayBuffer. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy

Offenders
warn(0)Set a Cross-Origin-Opener-Policy header to isolate the page from cross-origin windows.crossOriginOpenerPolicyHeader

Set a Cross-Origin-Opener-Policy header (typically same-origin) on the document response to isolate the page from cross-origin windows.

Cross-Origin-Opener-Policy (COOP) lets a page sever its window-group ties to cross-origin documents that opened it or that it opens. Together with Cross-Origin-Embedder-Policy it puts the page in a cross-origin isolated context, which mitigates cross-window side-channel attacks (Spectre) and unlocks high-resolution timers and SharedArrayBuffer. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Opener-Policy

Offenders
infoSet a Cross-Origin-Resource-Policy header to limit who may embed the page.crossOriginResourcePolicyHeader

Set a Cross-Origin-Resource-Policy header (same-origin, same-site or cross-origin) on the document response to limit who may embed it.

Cross-Origin-Resource-Policy (CORP) is a per-response opt-in that tells the browser which origins are allowed to embed the resource. It blocks cross-origin or cross-site no-cors embedding (img, script, iframe, etc.) and is one of the building blocks of cross-origin isolation. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Resource-Policy

Offenders
warn(0)Set a Permissions-Policy header to control which browser features the page can use.permissionsPolicyHeader

Set a Permissions-Policy header to control which browser features the page can use.

The Permissions-Policy response header (the successor to Feature-Policy) lets a site explicitly opt in or out of powerful browser features such as camera, microphone, geolocation, payment and clipboard. Setting a strict policy reduces the attack surface and limits what embedded third parties can do. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Permissions-Policy

Offenders
warn(0)Set a referrer-policy header to make sure you do not leak user information.referrerPolicyHeader

Set a referrer-policy header to make sure you do not leak user information.

Referrer Policy is a new header that allows a site to control how much information the browser includes with navigations away from a document and should be set by all sites. https://scotthelme.co.uk/a-new-security-header-referrer-policy/.

Offenders
warn(30)Use a strict Content-Security-Policy header to mitigate cross-site scripting (XSS) attacks.contentSecurityPolicyHeader

The policy allows 'unsafe-inline', which lets the browser execute inline scripts and styles directly from the page. Move to nonces or hashes plus 'strict-dynamic' so that inline injection cannot run. The policy allows 'unsafe-eval', which lets the page call eval() and Function(). Almost no application needs this; remove it.

A Content-Security-Policy response header tells the browser which sources of script, style, and other content are allowed. The most effective form is a strict CSP using nonces or hashes together with strict-dynamic; the worst is a missing header, with unsafe-inline and unsafe-eval close behind. https://web.dev/articles/strict-csp

Page info

Page info

TitleWikipedia, the free encyclopedia
GeneratorMediaWiki 1.47.0-wmf.3
Width1920
Height3604
DOM elements2328
Avg DOM depth14
Max DOM depth21
Iframes0
Script tags5
Local storage952.6 KB
Session storage0 b
Network Information APIunknown

Resource hints

3 hints
dns-prefetch
  • https://meta.wikimedia.org/
  • https://en.wikipedia.org/wiki/auth.wikimedia.org
preconnect
  • https://upload.wikimedia.org/

Technologies used to build the page

Data collected using Coach-core version 9.2.1. With updated code from Webappanalyzer 2026-05-04. Use --browsertime.firefox.includeResponseBodies html or --browsertime.chrome.includeResponseBodies html to help Wappalyzer find more information about technologies used.

Detected technologies

5 technologies
Visual Metrics | Google Web Vitals | Largest Contentful Paint | Browser metrics | Visual Elements | Server timings | 

Data from run 3

Visual Metrics

Visual progress
Visual progress at 0 s0.0s
Visual progress at 1.1 s1.1s
Visual progress at 1.3 s1.3s
Visual progress at 1.6 s1.6s
Visual progress at 1.9 s1.9s
Visual progress at 2.2 s2.2s
Visual progress at 2.4 s2.4s
Visual progress at 2.7 s2.7s
FCP0.87s
LCP1.66s
VC850.90s
0.0s0.5s1.1s1.6s2.2s2.7s

Google Web Vitals

from run 3

Largest Contentful Paint

When the page main content is rendered, collected via the Largest Contentful Paint API. Read more about Largest Contentful Paint.

1.661 sLCP render time

Phase breakdown

  • TTFB408 ms
  • Resource load delay1.125 s
  • Resource load duration127 ms
  • Element render delay2 ms

Element

Element type
<div>
Size (w × h)
72274
URL
https://upload.wikim...y_banner_2023.jpg
Load time
1.661 s

DOM path

body > div:eq(2) > div > div:eq(0) > div#siteNotice > div#centralNotice > div > div#wlm-de > a > div:eq(1)
LCP

The LCP element is highlighted in the screenshot. If nothing is highlighted the element was removed before the screenshot or the LCP API couldn't find it.

The Largest Contentful Paint API matched this image:

LCP element

Browser Metrics

Navigation Timing
Extra timings
User Timing marks
mwStartup841 ms
mwCentralNoticeBanner1.508 s

Server timings

2 entries
NameDurationDescription
cache0 mshit-front
host0 mscp3070

Custom metrics collected through JavaScript

There are no custom configured scripts.

Extra metrics collected using scripting

There are no custom extra metrics from scripting.

Visual Elements3
LargestImage120px-Mikel_Arteta_2021_%28cropped%29.png
Display time1.533 s
Position (x, y)1305, 427
Size (w × h)120 × 164
HTML snippet
<img alt="Mikel Arteta in 2021" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Mikel_Arteta_2021_%28cropped%29.png/120px-Mikel_Arteta_2021_%28cropped%29.png" decoding="async" width="120" height="164" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Mikel_Arteta_2021_%28cropped%29.png/250px-Mikel_Arteta_2021_%28cropped%29.png 2x" data-file-width="624" data-file-height="852">
LargestImage preview
Heading
Display time1.533 s
Position (x, y)676, 249
Size (w × h)288 × 49
HTML snippet
<h1 id="Welcome_to_Wikipedia" class="html-heading mw-html-heading"></h1>
LargestContentfulPaint
Display time1.667 s
Position (x, y)375, 91
Size (w × h)946 × 76
HTML snippet
<div class="wlm-image"></div>
Summary | Largest responses | Per content type | Per domain | Expires & last-modified | 

PageXray

How the page is built.

HTTP versionHTTP/2.0
Total requests39
Total domains4
Transfer size649.7 KB
Content size0 b
Missing compression0
Cookies290 third-party

Response codes

200
3897.4%
302
12.6%

Requests and sizes per content type

6 types
ContentHeader SizeTransfer SizeContent SizeRequests
html6.2 KB53.4 KB0 b1
css2.4 KB26.2 KB0 b2
javascript11.0 KB279.2 KB0 b8
image25.6 KB223.8 KB0 b20
favicon1008 B2.0 KB0 b1
svg6.9 KB63.9 KB0 b6
Total53.1 KB648.5 KB0 b38

Data per domain

4 domains
DomainTotal download timeTransfer SizeContent SizeRequests
en.wikipedia.org3.542 s417.6 KB0 b17
upload.wikimedia.org12.258 s227.6 KB0 b20
meta.wikimedia.org118 ms2.9 KB0 b1
auth.wikimedia.org185 ms1.6 KB0 b1

Expires & last-modified statistics

typeminmedianmax
Expires0 seconds0 seconds1 year
Last modified2 seconds9 weeks3 years

CPU