Vapi Phone Number Setup

Import phone numbers from Twilio, Vonage, or Telnyx, or use Vapi's built-in numbers to connect voice assistants to real phone calls.

Setup: Ensure VAPI_API_KEY is set. See the setup-api-key skill if needed.

Quick Start — Buy a Vapi Number

Vapi provides free phone numbers for testing with daily call limits.

curl -X POST https://api.vapi.ai/phone-number \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "vapi",
    "assistantId": "your-assistant-id",
    "name": "Main Support Line"
  }'

Import from Twilio

curl -X POST https://api.vapi.ai/phone-number \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "twilio",
    "number": "+11234567890",
    "twilioAccountSid": "your-twilio-account-sid",
    "twilioAuthToken": "your-twilio-auth-token",
    "assistantId": "your-assistant-id",
    "name": "Twilio Support Line"
  }'

Import from Vonage

curl -X POST https://api.vapi.ai/phone-number \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "vonage",
    "number": "+11234567890",
    "credentialId": "your-vonage-credential-id",
    "assistantId": "your-assistant-id",
    "name": "Vonage Support Line"
  }'

Import from Telnyx

curl -X POST https://api.vapi.ai/phone-number \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "telnyx",
    "number": "+11234567890",
    "credentialId": "your-telnyx-credential-id",
    "assistantId": "your-assistant-id",
    "name": "Telnyx Support Line"
  }'

Assign an Assistant

Every phone number can be linked to an assistant or squad for inbound calls:

curl -X PATCH https://api.vapi.ai/phone-number/{id} \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "assistantId": "your-assistant-id"
  }'

Or assign a squad:

curl -X PATCH https://api.vapi.ai/phone-number/{id} \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "squadId": "your-squad-id"
  }'

Phone Number Hooks

Configure automated actions when calls come in:

{
  "hooks": [
    {
      "on": "call.ringing",
      "do": [
        {
          "type": "say",
          "exact": "Please hold while we connect you."
        }
      ]
    }
  ]
}

Managing Phone Numbers

# List all phone numbers
curl https://api.vapi.ai/phone-number \
  -H "Authorization: Bearer $VAPI_API_KEY"

# Get a phone number
curl https://api.vapi.ai/phone-number/{id} \
  -H "Authorization: Bearer $VAPI_API_KEY"

# Update a phone number
curl -X PATCH https://api.vapi.ai/phone-number/{id} \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name": "Updated Name"}'

# Delete a phone number
curl -X DELETE https://api.vapi.ai/phone-number/{id} \
  -H "Authorization: Bearer $VAPI_API_KEY"

Inbound Call Flow

1. Caller dials your Vapi phone number
2. Vapi routes the call to the assigned assistant or squad
3. The assistant speaks its firstMessage
4. The conversation proceeds with the configured model, voice, and tools

Outbound Call Flow

1. Create a call via POST /call with phoneNumberId and customer.number
2. Vapi dials the customer from your phone number
3. When answered, the assistant begins the conversation

Free Number Limitations

• Cannot make international calls
• Daily call limits apply
• For production use, import your own Twilio/Vonage/Telnyx numbers

References

• Vapi Phone Numbers Docs
• Free Telephony
• Phone Number Hooks

Additional Resources

This skills repository includes a Vapi documentation MCP server (vapi-docs) that gives your AI agent access to the full Vapi knowledge base. Use the searchDocs tool to look up anything beyond what this skill covers — advanced configuration, troubleshooting, SDK details, and more.

Auto-configured: If you cloned or installed these skills, the MCP server is already configured via .mcp.json (Claude Code), .cursor/mcp.json (Cursor), or .vscode/mcp.json (VS Code Copilot).

Manual setup: If your agent doesn't auto-detect the config, run:

claude mcp add vapi-docs -- npx -y mcp-remote https://docs.vapi.ai/_mcp/server

See the README for full setup instructions across all supported agents.