Vapi Call Creation

Initiate outbound phone calls, web calls, and batch calls using Vapi’s API. Connect your voice assistants to real phone numbers and test them programmatically.

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

Quick Start — Outbound Phone Call

cURL

curl -X POST https://api.vapi.ai/call \
  -H "Authorization: Bearer $VAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "assistantId": "your-assistant-id",
    "phoneNumberId": "your-phone-number-id",
    "customer": {
      "number": "+11234567890"
    }
  }'

TypeScript (Server SDK)

import { VapiClient } from "@vapi-ai/server-sdk";

const vapi = new VapiClient({ token: process.env.VAPI_API_KEY! });

const call = await vapi.calls.create({
  assistantId: "your-assistant-id",
  phoneNumberId: "your-phone-number-id",
  customer: {
    number: "+11234567890",
  },
});

console.log("Call created:", call.id);

Python

import requests
import os

response = requests.post(
    "https://api.vapi.ai/call",
    headers={
        "Authorization": f"Bearer {os.environ['VAPI_API_KEY']}",
        "Content-Type": "application/json",
    },
    json={
        "assistantId": "your-assistant-id",
        "phoneNumberId": "your-phone-number-id",
        "customer": {"number": "+11234567890"},
    },
)

call = response.json()
print(f"Call initiated: {call['id']}")

Call Types

Outbound Phone Call

Requires an assistant, a Vapi phone number, and a customer number.

{
  "assistantId": "assistant-id",
  "phoneNumberId": "phone-number-id",
  "customer": {
    "number": "+11234567890",
    "name": "John Doe",
    "numberE164CheckEnabled": true
  }
}

Web Call

For browser-based calls — no phone number needed. Use the Vapi Web SDK on the client side.

{
  "assistantId": "assistant-id"
}

Client-side (JavaScript):

import Vapi from "@vapi-ai/web";

const vapi = new Vapi("your-public-key");
vapi.start("your-assistant-id");

Transient Assistant Call

Define an assistant inline instead of referencing a saved one:

{
  "assistant": {
    "name": "Quick Test",
    "firstMessage": "Hello! This is a test call.",
    "model": {
      "provider": "openai",
      "model": "gpt-4.1",
      "messages": [
        {
          "role": "system",
          "content": "You are a test assistant. Confirm the call is working and end politely."
        }
      ]
    },
    "voice": { "provider": "vapi", "voiceId": "Elliot" },
    "transcriber": { "provider": "deepgram", "model": "nova-3", "language": "en" }
  },
  "phoneNumberId": "phone-number-id",
  "customer": {
    "number": "+11234567890"
  }
}

Scheduled Calls

Schedule a call for a future time:

{
  "assistantId": "assistant-id",
  "phoneNumberId": "phone-number-id",
  "customer": {
    "number": "+11234567890"
  },
  "schedulePlan": {
    "earliestAt": "2025-06-15T14:00:00Z",
    "latestAt": "2025-06-15T15:00:00Z"
  }
}

• earliestAt — Earliest time to attempt the call (ISO 8601)
• latestAt — Latest time to attempt the call (optional)
• If using assistantId, the latest version of the assistant is used at call time
• For a fixed assistant config, use assistant (transient) instead

Batch Calls

Call multiple numbers in one request:

{
  "assistantId": "assistant-id",
  "phoneNumberId": "phone-number-id",
  "customers": [
    { "number": "+11234567890", "name": "Alice" },
    { "number": "+10987654321", "name": "Bob" },
    { "number": "+15551234567", "name": "Carol" }
  ]
}

Combine with schedulePlan for scheduled batch calls.

Call with Metadata

Pass custom data accessible during the call:

{
  "assistantId": "assistant-id",
  "phoneNumberId": "phone-number-id",
  "customer": {
    "number": "+11234567890"
  },
  "metadata": {
    "orderId": "ORD-12345",
    "department": "billing"
  }
}

Managing Calls

# List calls
curl "https://api.vapi.ai/call?limit=10" \
  -H "Authorization: Bearer $VAPI_API_KEY"

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

# Get call with transcript and recording
curl https://api.vapi.ai/call/{id} \
  -H "Authorization: Bearer $VAPI_API_KEY"
# Response includes: transcript, recordingUrl, summary, costBreakdown

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

Call Response

A successful call creation returns:

{
  "id": "call-uuid",
  "orgId": "org-uuid",
  "type": "outboundPhoneCall",
  "status": "queued",
  "assistantId": "assistant-id",
  "phoneNumberId": "phone-number-id",
  "customer": {
    "number": "+11234567890"
  },
  "createdAt": "2025-01-15T10:00:00Z"
}

Call statuses: queued → ringing → in-progress → ended

Compliance Warning

It is a violation of FCC law to dial phone numbers without consent in an automated manner. Review TCPA consent requirements before launching automated call campaigns.

References

• Vapi Outbound Calls Docs
• Call Features
• Voicemail Detection

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.