Finmo 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, a payin failed, etc.). Codes in the 5xx range indicate an error with Finmo's servers (these are quite rare).

A few 4xx errors that could be handled programmatically (e.g., a card is declined) include an error code that briefly explains the error reported.

HTTP Status Codes Summary

Status Code	Status	Description
200	OK	Everything worked as expected.
201	CREATED	The request has been fulfilled and resulted in new resources being created.
400	BAD REQUEST	The request was unacceptable, often due to missing a required parameter.
401	UNAUTHORIZED	No valid API key was provided.
402	REQUEST FAILED	The parameters were valid but the request failed.
403	FORBIDDEN	The API key doesn't have permission to perform the request.
404	NOT FOUND	The requested resource doesn't exist.
406	NOT ACCEPTABLE	The parameters were valid but the values were not acceptable.
409	CONFLICT	The request conflicts with another request (perhaps due to using the same idempotent key).
429	TOO MANY REQUESTS	This status is returned when your client exceeds the allowed request limits, indicating a violation of our rate limits. To maintain compliance, we recommend reviewing your implementation and optimizing request frequency to align with our guidelines. Avoid making excessive requests in a short period and contact the support team for higher rate limits or further assistance.
500, 502	SERVER ERRORS	Something went wrong on Finmo's end. (These are quite rare.)
503	SERVER ERRORS	Something went wrong on Finmo's end. (These are quite rare.)
499	CLIENT DISCONNECTED	This status indicates that your client disconnected the request because our server or an external partner took longer than expected to respond. Since our server may have already processed the request, this is not a retriable action. Before attempting a retry, please contact Finmo to verify the transaction status.
504	GATEWAY TIMEOUT	Similar to the 499 status code, this occurs when our partner takes longer than expected to respond, causing our server to time out the request. As the payment may have been processed despite the timeout, this request should not be retried automatically. Please confirm the transaction status with Finmo before retrying to prevent duplicate payments.

Note: Implement appropriate handling of the status codes in your integration. We recommend you to contact Finmo before retrying any payment-related requests that return a 499 or 504 status code.