| Return the required EHI response |
Your response must match the expected response for the message type. |
| Respond within the timeout window |
Authorization and real-time messages are time-sensitive. |
| Return deterministic responses |
For duplicates or retries, return the same logical response as the original processing. |
| Avoid malformed payloads |
Invalid response structure may prevent the response from being processed. |
| Avoid duplicate business impact |
Do not apply balance, block/reserve, ledger, or posting impact more than once. |