Keep-Alive
Both directions
States how long a reused connection should stay open.
| On the wire | Keep-Alive: … |
|---|---|
| Category | Both directions |
Headers that can appear on either side.
How to read this
- The first digit of a status code carries the meaning: 4 means the request, 5 means the server.
- 404 means "not there"; 403 means "there, but not for you". Swapping them makes debugging slower.
- Header names are case-insensitive — Content-Type and content-type are the same header.
- Caching and CORS problems usually come down to one header line, visible in the browser’s network tab.
Frequently asked questions
Q. What does HTTP Keep-Alive mean?
States how long a reused connection should stay open.
Q. What does Keep-Alive look like on the wire?
It travels as Keep-Alive: …
Q. Where does Keep-Alive appear?
In both directions.
Q. What group does Keep-Alive belong to?
The both directions group; the rest of that group is listed further down.