Error contract

Webhook errors use real HTTP status codes plus a stable string code. Branch on code, not on message (the message is human-readable Vietnamese and may change).

{ "code": "DAILY_CAP_EXCEEDED", "message": "Vượt hạn mức theo ngày" }

HTTP	code	When	What to do
400	INVALID_PAYLOAD	Body isn’t valid JSON or fails schema.	Fix the payload; don’t retry as-is.
401	INVALID_SIGNATURE	Missing/invalid signature, or unknown apiKeyId.	Check secret & signing string; verify you signed the exact bytes.
401	TIMESTAMP_OUT_OF_RANGE	X-Timestamp outside ±5 min.	Sync clock (NTP), resend with a fresh timestamp.
403	PARTNER_SUSPENDED	Your partner account is suspended.	Contact Eventista.
403	TENANT_NOT_ALLOWED	tenantId not allow-listed, or no caps configured.	Check tenantId; contact Eventista to enable.
403	EP_DISABLED	The tenant’s EP wallet is turned off.	Contact Eventista / the tenant admin.
409	IDEMPOTENCY_CONFLICT	orderId reused with a different payload.	Use a new orderId, or resend the identical payload.
422	AMOUNT_BELOW_MIN	amount < 1000 — would credit 0 EP.	Only send amount ≥ 1000.
422	PER_TX_CAP_EXCEEDED	Credited EP exceeds perTx.	Lower the amount or request a higher cap.
429	DAILY_CAP_EXCEEDED	Per-partner or per-user daily cap reached.	Retry next Vietnam day, or request a higher cap.
422	WALLET_FROZEN	The recipient’s wallet is frozen by an admin.	Do not retry; contact Eventista.
503	TX_CONFLICT	Transient DB contention.	Retry with backoff (same orderId).
404	NOT_FOUND	Status lookup for an unknown orderId.	Verify the orderId.