Backoff header on heavy load¶
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
The back-off time is configurable on the server.
In other implementations at Mozilla, there was
X-Backoff but the
X- prefix for
header has been deprecated since.
Retry-After header will be added if response is an error (>=500).
See more details about error responses.