The following status codes can be returned in HTTP responses.
|HTTP Code||HTTP Description||Notes|
|2xx||OK||Not an error; returned on success.|
|400||Bad Request||Bad Request/Invalid Arguments (merchant, service, slot not found, trying to book an invalid slot, cancelling a booking that never existed).|
|401||Unauthorized||Unauthenticated (invalid credentials, retry login). The request does not have valid authentication credentials for the operation.|
|403||Forbidden||Permission denied/forbidden (caller is known and rejected). This
response must not be used for rejections caused by exhausting some
|404||Not Found||Not found (Resource not found, invalid url, including invalid RPCs)|
|409||Conflict||The operation was aborted, typically due to a concurrency issue such as a sequencer check failure or transaction abort.|
|429||Too Many Requests||Some resource has been exhausted, perhaps a per-user quota, or perhaps the entire file system is out of space.|
|499||Client Closed Request||The operation was cancelled, typically by the caller.|
|500||Internal Server Error||Internal errors. This means that some invariants expected by the underlying system have been broken. This error code is reserved for serious errors.|
|501||Not Implemented||The operation is not implemented or is not supported/enabled in this service.|
|503||Service Unavailable||The service is currently unavailable. This is most likely a transient condition, which can be corrected by retrying with a backoff.|
|504||Gateway Timeout||The deadline expired before the operation could complete. For operations that change the state of the system, this error may be returned even if the operation has completed successfully. For example, a successful response from a server could have been delayed long enough for the deadline to expire.|
Sometimes multiple error codes may apply. Services should return the most specific error code that applies.