API endpoints require the use of the Account Id in the endpoint URL path.
Step 1 - Getting your Account Id
All ReachMail accounts can access the /Administration/Users/Current endpoint to retrieve their Account Id. The Account Id is not your Account Key.
Step 2 - Sending a Message
Step 3 - Reporting
EasySMTP Reporting endpoints accept dates as filter arguments in the request. Retrieve a summary, bounces, open, clicks, and opt out reports. See the Summary Report endpoint documentation.