Tested 2026-07-30 19:02:57 using Chrome 150.0.7871.186 (runtime settings)
The red band on the timeline marks when the main thread was busy with long tasks: moments when the page could not paint or respond, however the video looks.
Download videoUse --filmstrip.showAll to show all filmstrips.
Click a frame to seek the video to that moment. The dot marks frames where the page changed visually.
Rendering was not meaningfully delayed. First paint landed at 475 ms on a 206 ms first byte; the 1 render-blocking request was done by 344 ms and the remaining ~131 ms is style and layout work. The largest paint followed at 600 ms.
Want to see how much CSS style-recalculation work delayed FCP and LCP, plus CPU long tasks? Run with --cpu.
Blocking requests delay both paints: the browser renders nothing until they arrive, so they push First Contentful Paint and everything after it, including the largest paint (LCP). Requests that block the parser inside the body stall everything after them in the document. Load JavaScript with defer or async, and keep non-critical CSS off the critical path with media attributes. Bars show when each request loaded on a clock that runs to the last paint (the dashed line is FCP, the clock ends at LCP); the gap after the bars is style and layout work.
| Request | When it loaded | Transfer | Download |
|---|---|---|---|
document | 188 ms | 6.1 KB | 187 ms |
NpD8aMgW5S.cssblocking | 75 ms | 5.9 KB | 75 ms |
user-timing-header.jsblocks parser in body | 72 ms | 223 B | 72 ms |
LCP resource | 126 ms | 34.4 KB | 126 ms |
0150 ms300 msFCP 475 msLCP 600 ms |
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.
longTasksThe page has 1 CPU long task with the total of 64 ms. The total blocking time is 0 ms and 1 long task before first contentful paint with total time of 64 ms. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. Use Geckoprofiler for Firefox or Chromes tracelog to debug your long tasks.
Long CPU tasks locks the thread. To the user this is commonly visible as a "locked up" page where the browser is unable to respond to user input; this is a major source of bad user experience on the web today. However the CPU Long Task is depending on the computer/phones actual CPU speed, so you should measure this on the same type of the device that your user is using. To debug you should use the Chrome timeline log and drag/drop it into devtools or use Firefox Geckoprofiler.
unnecessaryHeadersThere are 9 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.
nelHeaderSet a NEL header (paired with Reporting-Endpoints) to collect connection-level error reports from the field.
The NEL (Network Error Logging) response header tells the browser to record connection-level failures (DNS, TLS, HTTP errors) and ship them to a reporting endpoint. NEL pairs with the Reporting-Endpoints / Report-To header — the page declares the endpoint group and NEL points at it. Together they give you visibility into errors that never reach your origin server. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/NEL
reportingEndpointsHeaderSet a Reporting-Endpoints header (or the legacy Report-To header) so CSP reports, NEL data and other Reporting-API events have an endpoint to land at.
The Reporting-Endpoints response header (the successor to Report-To) names the URLs that browsers should POST reports to. Without it, CSP report-to directives, Cross-Origin-Opener-Policy reports, NEL data and other Reporting-API events have nowhere to go. The legacy Report-To header is still accepted for older Chromium versions. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Reporting-Endpoints
A snapshot of what the browser actually built for this page: the document, how big and deep the DOM tree is and what it kept in storage. Big, deep trees are slower to style and lay out, so the counts Chrome warns about carry a flag.
Document
What the page says it is and how large it rendered.
DOM structure
How much markup the browser has to build, style and lay out.
What the page stored on the client, and the network it was tested on.
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.
0.0s0.4s0.5s0.6sWhen the page main content is rendered, collected via the Largest Contentful Paint API. Read more about Largest Contentful Paint.
body > main > div:eq(0) > div > div:eq(0) > picture > img
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:
How much the page's content shifts as it loads, collected via the Cumulative Layout Shift API.
No layout shifts were detected on this page.
There are no custom configured scripts.
There are no custom extra metrics from scripting.
How the page is built.
| Header | Value |
|---|---|
accept-ranges | bytes |
age | 10059 |
cache-control | public,max-age=0,must-revalidate,no-transform |
cache-status | "Netlify Edge"; hit |
content-encoding | br |
content-length | 5610 |
content-security-policy | default-src 'self'; script-src 'self' 'wasm-unsafe-eval'; style-src 'self'; img-src 'self' data:; object-src 'none'; base-uri 'self'; frame-ancestors 'self' |
content-type | text/html; charset=UTF-8 |
cross-origin-embedder-policy | require-corp |
cross-origin-opener-policy | same-origin |
cross-origin-resource-policy | same-origin |
date | Thu, 30 Jul 2026 19:02:58 GMT |
etag | "651b72cff08aef13e551bbd7a84a7d36-ssl-df" |
permissions-policy | interest-cohort=() |
referrer-policy | no-referrer |
server | Netlify |
strict-transport-security | max-age=31536000; includeSubDomains |
vary | Accept-Encoding |
x-content-type-options | nosniff |
x-nf-request-id | 01KYT6H3GN8FPW42SJDDW05YB4 |
x-xss-protection | 1; mode=block |
| URL | Type | Transfer Size | Content Size |
|---|---|---|---|
| https://www.sitespee...8bRaVGAJ-500.avif | image | 34.4 KB | 34.2 KB |
| https://www.sitespee...5LbaEznK-180.avif | image | 6.9 KB | 6.8 KB |
| https://www.sitespeed.io/ | html | 6.1 KB | 24.7 KB |
| https://www.sitespee...ss/NpD8aMgW5S.css | css | 5.9 KB | 26.7 KB |
| https://www.sitespee.../sitespeed.io.ico | favicon | 2.9 KB | 6.4 KB |
| https://www.sitespee...W60XTv4C-200.avif | image | 2.3 KB | 2.2 KB |
| https://www.sitespeed.io/js/copy.js | javascript | 710 B | 1.7 KB |
| https://www.sitespee...-timing-footer.js | javascript | 290 B | 194 B |
| https://www.sitespee...-timing-header.js | javascript | 223 B | 102 B |
Transfer size59.6 KB
Content size102.9 KB
Requests9
| Content | Header Size | Transfer Size | Content Size | Requests |
|---|---|---|---|---|
| html | 0 b | 6.1 KB | 24.7 KB | 1 |
| css | 0 b | 5.9 KB | 26.7 KB | 1 |
| javascript | 0 b | 1.2 KB | 1.9 KB | 3 |
| image | 0 b | 43.5 KB | 43.2 KB | 3 |
| favicon | 0 b | 2.9 KB | 6.4 KB | 1 |
| Total | 0 b | 59.6 KB | 102.9 KB | 9 |
| Domain | Total download time | Transfer Size | Content Size | Requests |
|---|---|---|---|---|
| www.sitespeed.io | 998 ms | 59.6 KB | 102.9 KB | 9 |
| type | min | median | max |
|---|---|---|---|
| Expires | 0 seconds | 1 year | 1 year |
Includes requests done after load event end.
| Content | Transfer Size | Requests |
|---|---|---|
| html | 0 b | 0 |
| css | 0 b | 0 |
| javascript | 0 b | 0 |
| image | 6.9 KB | 1 |
| font | 0 b | 0 |
| favicon | 2.9 KB | 1 |
| Total | 9.8 KB | 2 |
Includes requests done after DOM content loaded.
| Content | Transfer Size | Requests |
|---|---|---|
| html | 0 b | 0 |
| css | 0 b | 0 |
| javascript | 0 b | 0 |
| image | 6.9 KB | 1 |
| font | 0 b | 0 |
| favicon | 2.9 KB | 1 |
| Total | 9.8 KB | 2 |
Third party requests categorised by Third party web version 0.29.2.
No third-party requests detected
Every request on this page resolved to a first-party domain. There are no entries in Third party web to attribute, no third-party tools to enumerate, and no third-party cookies set. If you expected to see entries here you can fine-tune the first-party domain list with --firstParty.
Calculated using .*sitespeed.* (use --firstParty to configure).
| Content | Header Size | Transfer Size | Content Size | Requests |
|---|---|---|---|---|
| html | 0 b | 6.1 KB | 24.7 KB | 1 |
| css | 0 b | 5.9 KB | 26.7 KB | 1 |
| javascript | 0 b | 1.2 KB | 1.9 KB | 3 |
| image | 0 b | 43.5 KB | 43.2 KB | 3 |
| font | 0 b | 0 b | 0 b | 0 |
| favicon | 0 b | 2.9 KB | 6.4 KB | 1 |
| Total | N/A | 59.6 KB | 102.9 KB | 9 |