Basic Calling

FreeClimb is capable of handling both inbound and outbound calls.

Inbound calls are those that are received and handled by FreeClimb. Outbound calls are those initiated by FreeClimb to the appropriate party and handled in response to the client’s request.

Inbound calls

Whenever someone calls a FreeClimb phone number, the call is handled by the FreeClimb platform. FreeClimb invokes the inbound webhook provided by you to

  • Provide details about the incoming call
  • Obtain instructions on how to handle the incoming call

Your client application then processes FreeClimb’s request and returns a call control script (written using the Performance Command Language, PerCL) that contains the requested telephony instructions. When FreeClimb receives the response, it executes the instructions in the script sequentially, responding to the call precisely as required by the client application.

Handling multiple phone numbers

You can associate one or more phone numbers with the FreeClimb application you register. A FreeClimb application (which is simply a set of configuration data and URLs that FreeClimb invokes) encapsulates configuration information. Any changes you make are applied to all affiliated phone numbers (e.g., how calls to those numbers are handled).

Outbound calls

There are two ways to make outgoing calls in FreeClimb. You can:


Trial accounts can make outbound calls to verified numbers only. Verified numbers can be added through your dashboard.

To make an outgoing call using the RESTful API’s Make a Call resource, you will need to specify the FreeClimb application you registered that should be used to make the call.

You can also make outbound calls using the PerCL OutDial command. This command tells FreeClimb to send a request to the callConnectUrl attribute specified by the OutDial command. For more information on the webhooks related to OutDial, see Calls.

Please note that international calling is disabled by default. If you would like to enable international calling, please contact support.

Use cases

You can use FreeClimb’s inbound and outbound calling features independently of one another, but you can also use them together to meet your specific telephonic needs. For more information on connecting calls, see the Conferences resource.

For example, you might use inbound calls to allow customers to call in and make a payment.

However, outbound calls can assist you with things like campaigns. If you have a phone list and you want to reach your users with a pre-recorded message, you can do so with outbound dialing.

Finally, FreeClimb can combine both inbound and outbound calls. For example, you can have someone call in to FreeClimb, and FreeClimb will place an outbound call to a second party. FreeClimb then connects the first party with the second party so they can speak to each other.

This feature is sometimes used by companies to route customer calls; the customer calls into a customer care number, and rather than getting directly connected to an agent, the customer may first interact with an automated telephony system before being routed to the agent. In this example, FreeClimb would initiate an outbound call to the agent and then connect the two calls together.

Ready to try basic calling with FreeClimb?

Explore the Calls API Reference.

Try one of our basic calling code snippet how-to guides: