Using Developer Tools
Developer tools for using APIs are available in the UI. Each resource is listed with operations organized by verb type. The Headers tab will allow you to see the relevant headers and edit them in the UI. If you are creating or updating an object the Body tab will list the properties in JSON format.
Since LogiSense Billing is an API first platform, all operations are logged whether those operations are from the UI or an external application. When developing it can be useful to perfrom an operation in the UI and then look up the request body and headers in the Json API log. Navigate to Operations > Logs and find the request. The request tab will include the details of the request header and body.