How can we access salesforce API logs?
How can we monitor salesforce API logs from which we can access and check whether all calls are reaching SFDC, which are supposed to be sent by a hosting service to the SFDC lead object through the SFDC API?
You can use EventMonitiring API, a paid feature, to access a complete log of all the calls made for a day. To get a more general overview, you can see the API Usage Report from Reports->Administrative Reports->API Calls Made Within Last 7 Days. Another way to check this is to enable the debug log for the user the application uses to log in as under setup ->Monitoring->Debug Log. It can track a maximum of 20 API calls. Click the reset link to reset the limit and capture more logs.