That’s exactly what a 503 is. 503 means that the server was relying on connecting some other service, which did not respond in time. Server Error 5xx Checked up on Wikipedia and the listing there seems to imply that a 504 would be the one I’m thinking of. Quite possibly the link over is outdated. … Read more
The correct one is 303. I use it and haven’t found any compatibility problems with UAs newer than Netscape 4 (1998, released 17 years ago). If you use 302, you’re risking that UA will re-send POST to the new URL instead of switching to GET. Still, if you’re worried about HTTP/1.0 clients (which don’t support … Read more
If it’s for a well-defined and -documented API, 202 sounds exactly right for what’s happening. If it’s for the public Internet, I would be too worried about client compatibility. I’ve seen so many if (status == 200) hard-coded…. In that case, I would return a 200. Also, the RFC makes no indication that using 202 … Read more