The MobilePay PoS API is a REST interface over HTTPS using JSON format as input and output. The HTTP status codes 200, 400, 401 and 500 are used.
There are other HTTP status codes that must be handled by the PoS.
HTTP status code 200: Used in response to a successfully requests.
HTTP status code 400: Used in response to request dealing with other problems (used MerchantId is unknown etc.).
In the case of a 400 code the service will return JSON with the following format describing the error:
HTTP status code 401: Used in response to unauthorized requests (as used HMAC could not be validated due to used APIKEY is invalid etc.).
HTTP status code 500: Used in response if an internal error at MobilePay has occurred (database server down etc.)
HTTPS communications are done via port 443, which is of benefit for those environments which block non-web Internet connections using a firewall.