In the developer console, I am only able to view the logs of an API call that I made from within the developer console (tests) or from workbench. But when I make a call from Postman, I do not see any logs to view. How can I view logs of API calls that are made from external resources like Postman?
In the Developer Console, uncheck Debug > Show My Current Logs Only. Any API calls that generate logs from this point on should appear in the Developer Console.
Alternatively, you can set Trace Flags in Setup > Monitoring > Debug Logs, and view the logs generated there.
Note that not all actions generate logs, such as running a query or describing an object. You need to actually perform some sort of DML or execute a class.