Response Time Checker / Glossary
Server wait (server time)
The time between sending the request and receiving the first byte, minus one network round trip: an estimate of how long the server spent building the response. A Server-Timing header, when present, gives the server's own figures.
How we measure it
The wait phase of each sample minus the connection round trip, as a median; Server-Timing entries are shown as the server reports them.
What good looks like
Our bands: excellent under 100 ms, good under 250 ms, fair under 500 ms, slow above.
How to improve it
- A full-page cache for pages that are the same for everyone.
- An object cache (Redis, Memcached) for repeated queries.
- Fix slow database queries (the slow-query log names them).
- Enough workers for the traffic; avoid serverless cold starts on the main page.
Measure your site
Three cold samples, every phase, and a diagnosis of what is slow.
Open the Response Time Checker