How can I debug my application?

Twilio provides two primary tools for debugging the interaction between your application and Twilio: the App Monitor and the Request Inspector.

App Monitor

The App Monitor, located under “Dev Tools,” allows you to find more information about requests that generated an error.

Under the Errors section you will see a list of all the times your application has seen this error message. Click on the message you want to inspect to see full details about the request, response type, and the calls where this error happened.

Request Inspector

To debug errors associated with specific calls, Twilio records all responses received by your application in the Request Inspector. You can access the Request Inspector by navigating to your call logs and selecting a specific call.


The Request Inspector lists all requests made by Twilio. To view your application’s response to a particular request, expand the ‘Response’ subheading under the request.

inspector details

You can also use the Request Replay feature to replay a request and see a side-by-side difference between the saved request and the new request.  The replayed request is identical to the original:  Twilio will send all the same header and request information.

You can also play the request back against a different endpoint, so you can test a failed production request against your development server.