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Website speed test

How fast a page answers a crawler: time to first byte, the whole page, its weight, compression and redirects.

One request, taken apartExample
Where the time goes
First byte at 340 ms
DNS
20 ms
Connect
30 ms
TLS
40 ms
Server
250 ms
Download
60 ms
Where 340 ms lands
  1. Under 200Quick
  2. 200 to 800Good
  3. 800 to 1,800Needs work
  4. Over 1,800Poor

Good under 800 and poor over 1,800, as Google counts a first byte. Not drawn to scale.

Everything before the download is what a crawler waits through before it reads a word. Here most of it is the server, which caching would cut.

What does it check?

Rules from the rulebook, and how many of the sites mttr has read miss each.

  1. Speed up the serverCache pages or speed up the server. Crawlers give a slow site fewer visits.
    16%of sites miss it
  2. Compress pagesTurn on gzip or Brotli for HTML on the server or CDN.
    4%of sites miss it

Questions

What is time to first byte?

How long a server takes to begin answering. It is what a crawler waits for before it reads a word.

How fast is fast enough?

Google counts a first byte under 800 milliseconds as good. Under 200 is quick.

Is this the same as Core Web Vitals?

No. Core Web Vitals measure a page in a browser, as a person sees it load. This measures how the server answers a crawler, which comes first.

The whole site

One page is one part. A read checks every page against the whole rulebook and says what to fix first.

Read a whole site