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Chirp provides APIs for making and receiving phone calls, with support for PSTN, WebRTC, and WhatsApp channels.

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Getting Started

Making Calls

Initiate outbound calls to any phone number or channel

Receiving Calls

Handle inbound calls with webhooks and call commands

Call Commands

Control active calls with answer, hold, transfer, and more

Recordings

Record calls and access recording files

Voicemails

Access and manage voicemail messages

Webhooks Setup

Configure webhooks for real-time calling event notifications

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Channels

Chirp supports three calling channels. You can make calls within the same channel or across different channels. PSTN Traditional phone network calls. Use standard E.164 phone numbers to call landlines and mobile phones worldwide. WebRTC Browser and app-based calling over the internet. Enables real-time voice communication without a traditional phone line. WhatsApp Voice calls over WhatsApp. Reach users on WhatsApp using their phone number as the identifier.
Cross-channel calls are supported. For example, you can initiate a call from a WebRTC client to a PSTN phone number, or from a PSTN number to a WhatsApp user.

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Prerequisites

Before you start making and receiving calls, you need:
  • An application with calling enabled
  • A phone number assigned to your application
  • An API key for authentication (sk_live_app_* or sk_test_app_*)
See Managing Phone Numbers to assign a number to your application.