Callr Docs

Build on Callr

Three ways to add voice and messaging to your platform. Pick one, or combine them.

REST API

Callr API

Buy phone numbers, send SMS, manage recordings and audio files, and receive webhooks from your backend.

Call flows in YAML

Callr Actions

Describe what happens on a call or an SMS: menus, forwarding, recording, HTTP requests. Run it on your numbers or from the API.

Voice AI & SIP

AI agents and SIP

Answer calls with an AI agent, or connect your numbers to OpenAI, ElevenLabs, Vapi or your own PBX over SIP.

Start from a use case

Step-by-step guides with a complete, working scenario.

Build an IVR menuPress 1 for sales, 2 for support. Connect two numbersClick-to-call from your application. Record and transcribeRecording, transcript and AI summary. Track callsOne number per campaign, data pushed to you. Broadcast callsReminders and alerts started from the API. Conference callsRooms with PIN codes and prompts. Send and receive SMSFrom the API or inside a call flow. Mask phone numbersConnect buyers and sellers privately.

Callr Actions

A phone menu, in YAML

A scenario is a YAML file. Each branch is a list of actions, results go into variables, and conditions route the call.

Validation and inline documentation in the editor
Live debugger on every call
Templates for IVR, voicemail, AI agents and call tracking

Explore Callr Actions Open the editor

variables:
  $sales: '+33199004242'
  $support: '+33199004243'
branches:
  inbound-call:
    actions:
      - action: gather@v4
        params:
          maxDigits: 1
          tts:
            text: Press 1 for sales, or 2 for support.
        result: $menu
      - action: dial@v2
        params:
          targets:
            - number: "${{ $menu.input == '1' ? $sales : $support }}"
              timeout: 30
        result: $dial

Resources

Everything else you need while you build.

RecipesShort, runnable API walkthroughs. ChangelogNew actions, versions and API changes. MCP serverUse these docs from your AI assistant. SupportTalk to the Callr team.