The Pacejet API uses standard HTTP response codes to communicate successful transaction results in combination with response content detail where appropriate. Because Internet latency and occasional timeouts across the web can occur, the best-practice is to include appropriate retry logic in integrations to ensure transaction integrity. For example, your application should gracefully handle any transient 504 error (server timeout) or other errors with a retry.
API Error Codes can be found in the API Endpoint Spreadsheet which can be found in the attachment below.