Creating Your First Application

Tropo's WebAPI is built around a request/response model using JSON as the data format; Tropo sends JSON to your application, your application responds with JSON instructions telling Tropo what to do, Tropo sends back results, and so on.

At the absolutely simplest level, your application can be a .json file with just the following code:

   "tropo":[{"say":{"value":"Guess what?"}}]

That app will answer a call, play a message using our Text To Speech (TTS) engine and an audio file to the caller and then disconnect. Getting this script running is just as easy - add the .json file with the above code to your webserver (or use an SSH tunnel service like Ngrok), then follow these instructions:

Lets walk you through creating an app that uses the previous script. If you haven't already registered for an account, you can do so for free at

Once you're logged into your Tropo account, you'll want to create your test application:

  1. Start by clicking on the "My Apps" link along the top, then select "Create application" in the dropdown.
  2. Give the app a name, then select Tropo WebAPI from the two options that follow.
  3. In the empty field below the WebAPI description, add your URL - this needs to point to an application actively available on your external web server.

    Note that this will vary depending on whether you're using a library or not, and in some cases whether you're using a framework. For example, if you're using Limonade with PHP, your URL would need to include the webserver URL, the PHP file name, and the resource name, like

  4. Next we'll add a phone number, to make it easy to call and test the app. Make sure to select a number that can receive voice calls. Start by selecting your preferred country from the Country drop down, followed by the region in the Region drop down. Don't see your country in the list? Tropo is adding new countries constantly, and only countries with available numbers appear here. Contact support to request a specific country.
  5. Click the Finish button at the bottom left of the screen to create the app.
  6. That's it! Give the phone number a call to test it out!