Supplying credentials for an API call

For testing APIs, I use a tool called Postman. Its free and available on the Chrome Webstore. Install and launch the app. To test an api call which requires authentication, turn on the Interceptor in Postman

This will prompt for a plugin to be installed in Chrome.

Once you do that, login to your application in Chrome. The login credentials will be passed on to Postman and you can proceed with the API call testing.