API preface

Identification and authentication of the caller

All requests must include an Authorization header with the API key issued by Gate for the specific merchant connection point (merchant terminal):

Authorization: Bearer <MERCHANT_API_KEY>.

Idempotency

referenceId is treated as the unique request identity per merchant terminal. Re-registering a create payment or create payout with an already used referenceId is treated as a duplicate and returns duplicate_request.

Error Handling

Generic error envelope with fields code, name, and English description is used for non-200 responses:

{
  "code": "1004",
  "name": "duplicate_request",
  "description": "Duplicate request."
}

Error codes

Code	Name	Description
1000	processing_error	Processing Error.
1002	incorrect_request	The request parameters didn’t validate.
1003	unauthorized	Unauthorized access. Credentials missing or invalid.
1004	duplicate_request	Duplicate Request.
1005	payment_method_not_supported	Payment method is not supported.
1006	currency_not_supported	Currency is not supported.
1007	invalid_currency	The currency value specified is not valid.
1008	invalid_amount	The amount value specified is not valid.
1009	interface_operation_not_supported	The operation is not supported for the interface.
1010	bin_not_found	No card scheme found for provided BIN value.
1104	payment_not_found	Payment not found for provided identity value.
1105	invalid_payment_state	The payment is in a state that does not allow this operation.
1106	payout_not_found	Payout not found for provided identity value.
3001	declined_by_acquirer	Declined by acquirer.
4001	declined_by_issuer	Declined by issuer.
4002	issuer_insufficient_funds	Insufficient funds.
4003	issuer_invalid_card_number	Card number is invalid.
4004	issuer_card_expired	Card is expired.
4005	issuer_limits_reached	Issuer limits are reached.
4006	issuer_card_stolen	Card is declined by issuer.
4007	issuer_invalid_security_code	Invalid security code.
5001	declined_by_3ds	Declined by 3DS.
7001	declined_by_antifraud	Declined by antifraud.