The iVeri Web API Developers Guide, deals only with request and response message using the REST API.
To make use of the REST API, a UserGroup, together with user credentials (username and password) are required for the gateway you will be connecting to. This information is usually captured and supplied by the support help desk.
The various parameters (amount, time of transaction, card details etc.) that need to be set when performing a transaction, are returned by the gateway, as well as transaction logic, are dealt with in detail in the iVeri Client Developers Guide.
Interaction between the Miura POS device is dealt with in the iVeri mPress API Developers Guide