AddPay uses conventional HTTP response codes to indicate the success or failure of an API request. In general: Codes in the
2xx range indicate success. Codes in the
4xx range indicate an error that failed given the information provided (e.g., a required parameter was omitted, validation failed, etc.). Codes in the
5xx range indicate an error with our servers (these are rare).
These errors are in relation to general HTTP API request errors and are not associated with transaction status and/or transaction response errors, see the specific API reference article per resource endpoint for resource error status keys and codes.