HTTP status for exponential authentication timeout

Question

On my web server, all API requests made related-to and before authentication are subject to an exponential timeout.

For example, after a user unsuccessfully logs in a few times, the delay before the server will accept a request will go from 2 to 4, 8, 16 seconds and so on.

Any requests made during these delay periods will be immediately rejected by the server with a rety-after header passed.

What HTTP status code should the server return in this case?

Answer 1

I think it should be

429 Too Many Requests

http://developer.mozilla.org/en-US/docs/Web/HTTP/Status/429