The Sieve API uses the following error codes:

Error CodeMeaning
200OK
400Bad Request — Your request is invalid.
401Unauthorized — Your API key is wrong.
403Forbidden — The project requested is hidden for administrators only or doesn’t exist.
406Not Acceptable — You requested a format that isn’t json.
408Timeout — Your request to an await endpoint has timed out.
429Too Many Requests — You’re sending requests too quickly! Slow down!
500Internal Server Error — We had a problem with our server. Try again later.
503Service Unavailable — We’re temporarily offline for maintenance. Please try again later.