
Description
Create outbound phone calls, web calls, and batch calls using the Vapi API. Use when making automated calls, testing voice assistants, scheduling call campaigns, or initiating conversations programmatically.
SKILL.md
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_KEYis set. See thesetup-api-keyskill 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", "version": 2 },
"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: artifact.transcript, artifact.recordingUrl,
# analysis.summary, and costBreakdown when those outputs are enabled
# 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
Additional Resources
Vapi provides a documentation MCP server that gives compatible AI agents access to the Vapi knowledge base. Use its documentation search for advanced configuration, troubleshooting, SDK details, and anything beyond this skill.
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 Vapi MCP integration guide for setup instructions across supported agents.
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