Website Speed Test

A performance report based on what can genuinely be measured about a website from a browser: HTTP status, redirects, response headers, DNS records, network timing and a clearly explained diagnostic score. Measurements that are not possible (like Cross-Origin Core Web Vitals) are reported as “Not available in this test” instead of being invented.

Test a website URL

The test makes three server-side requests through the microLink API, one DNS query via Google Public DNS, and attempts a direct browser load of the page (only possible when the target allows cross-origin access). Allow 20–60 seconds; heavy comparisons may take longer.

What this tool measures

  • Server/API-measured: final HTTP status, redirect chain, response headers (Content-Type, Content-Length, Server), final URL — collected by the microLink API from its own servers and clearly labeled.
  • Browser-measured: the round-trip time of each request from your browser through the API to the site, and — when the site allows — a direct browser load with DNS, connect, TLS and TTFB timing from the Resource Timing API.
  • DNS API: real A and AAAA records for the hostname from Google Public DNS.

What it does not measure

  • FCP, LCP, INP and CLS of the target page (they require rendering the page in a real browser session; shown as “Not available in this test”).
  • An official Google score — the Website Diagnostic Score is this site’s own simplified calculation, with every factor and its weight shown on the report.
  • The experience of every visitor — results depend on your connection, the API server’s location and the target’s load at that moment.

Limitations & transparency

CORS rules prevent this page from loading another website inside its own session, and it cannot render pages like Chrome's lab tools do. Those restrictions are respected, never bypassed. Round-trip times always include more than just the target site (your connection + the API provider), and each measurement row carries its source label so you always know who measured it.

The tested URL is sent to microLink and dns.google. This site stores nothing. See the Privacy Policy.

Website performance terms, explained

TTFB (Time To First Byte)
The delay until the server's first byte of response arrives. High TTFB points at server processing, hosting or DNS setup rather than page size.
Page load time
How long the full page takes to become usable. It combines server response, HTML, CSS, JavaScript, images and third-party requests.
LCP (Largest Contentful Paint)
The moment the largest visible element (a hero image, a heading) paints. It is Google's main loading metric and is measured on real rendered pages — which is why it is not available in this cross-origin test.
INP (Interaction to Next Paint)
How fast the page answers taps and clicks — a responsiveness metric gathered from real user interactions.
CLS (Cumulative Layout Shift)
How much the layout jumps while loading (images without dimensions, late ads, webfonts). Large shifts are annoying and hurt the user experience.
Why images affect performance
Images are usually most of a page's weight. Uncompressed originals and missing width/height attributes slow loading and cause layout shift.
Why JavaScript affects loading
Scripts block parsing and rendering, and heavy frameworks add download + execution time. Fewer, smaller, deferred scripts load faster.
Why hosting affects response time
The server's CPU, location (distance to visitors), caching and CDN all change TTFB and total load time. A slow host makes an otherwise light page feel slow.

FAQ

Why is TTFB missing for my site?
TTFB is read from the Resource Timing API, which only reports it when the target server allows cross-origin timing (Timing-Allow-Origin header). Most servers do not send it, so the browser deliberately can't see it. The report says so instead of estimating.
Is the Website Diagnostic Score a Google score?
No — and it says so on the report. It is a simplified 0–100 score computed only from the checks this page performed (HTTPS, status, redirects, round-trip time, DNS, content type). Every factor, maximum weight and measured value is shown in a table.
Why did my WordPress site score lower after I slowed the test with 3 requests?
The score uses the average of three round trips so a single slow response doesn't skew it. A bad average usually reflects server load or a slow host — which is exactly what the round-trip factor is meant to surface.
How fast should my site be?
As a rough practical guide: under ~2 seconds to first meaningful content feels fast to most visitors. This page cannot measure that directly, but the checks it performs (status, redirects, TTFB when allowed, DNS health) cover the common speed killers.

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