A Backoff
header will be added to the success responses (>=200 and <400) when the server is under heavy load. It provides the client with a number of seconds during which it should avoid doing unnecessary requests.
Backoff: 30
Note
The back-off time is configurable on the server.
Note
In other implementations at Mozilla, there was X-Weave-Backoff
and X-Backoff
but the X-
prefix for header has been deprecated since.
A Retry-After
header will be added to error responses (>=500), telling the client how many seconds it should wait before trying again.
Retry-After: 30