Vapi Webhook / Server URL Setup Configure server URLs to receive real-time events from Vapi during calls — transcripts, tool calls, status changes, and end-of-call reports. Setup: Ensure VAPI_API_KEY is set. See the setup-api-key skill if needed. Overview Vapi uses "Server URLs" (webhooks) to communicate with your application. Unlike traditional one-way webhooks, Vapi server URLs support bidirectional communication — your server can respond with data that affects the call. Where to Set Server URLs On an Assistant curl -X PATCH https://api.vapi.ai/assistant/ { id } \ -H "Authorization: Bearer $VAPI_API_KEY " \ -H "Content-Type: application/json" \ -d '{ "serverUrl": "https://your-server.com/vapi/webhook", "serverUrlSecret": "your-webhook-secret" }' On 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 '{ "serverUrl": "https://your-server.com/vapi/webhook" }' At the Organization Level Set a default server URL in the Vapi Dashboard under Settings > Server URL . Priority order: Tool server URL > Assistant server URL > Phone Number server URL > Organization server URL. Event Types Event Description Expects Response? assistant-request Request for dynamic assistant config Yes — return assistant config tool-calls Assistant is calling a tool Yes — return tool results status-update Call status changed No transcript Real-time transcript update No end-of-call-report Call completed with summary No hang Assistant failed to respond No speech-update Speech activity detected No Webhook Server Example (Express.js) import express from "express" ; import crypto from "crypto" ; const app = express ( ) ; app . use ( express . json ( ) ) ; app . post ( "/vapi/webhook" , ( req , res ) => { const { message } = req . body ; switch ( message . type ) { case "assistant-request" : // Dynamically configure the assistant based on the caller res . json ( { assistant : { name : "Dynamic Assistant" , firstMessage : Hello ${ message . call . customer ?. name || "there" } ! , model : { provider : "openai" , model : "gpt-4.1" , messages : [ { role : "system" , content : "You are a helpful assistant." } , ] , } , voice : { provider : "vapi" , voiceId : "Elliot" } , transcriber : { provider : "deepgram" , model : "nova-3" , language : "en" } , } , } ) ; break ; case "tool-calls" : // Handle tool calls from the assistant const results = message . toolCallList . map ( ( toolCall : any ) => ( { toolCallId : toolCall . id , result : handleToolCall ( toolCall . name , toolCall . arguments ) , } ) ) ; res . json ( { results } ) ; break ; case "end-of-call-report" : // Process the call report console . log ( "Call ended:" , { callId : message . call . id , duration : message . durationSeconds , cost : message . cost , summary : message . summary , transcript : message . transcript , } ) ; res . json ( { } ) ; break ; case "status-update" : console . log ( "Call status:" , message . status ) ; res . json ( { } ) ; break ; case "transcript" : console . log ( `

message . transcript } ) ; res . json ( { } ) ; break ; default : res . json ( { } ) ; } } ) ; function handleToolCall ( name : string , args : any ) : string { // Implement your tool logic here return Result for ${ name } ` ; } app . listen ( 3000 , ( ) => console . log ( "Webhook server running on port 3000" ) ) ; Webhook Server Example (Python / Flask) from flask import Flask , request , jsonify app = Flask ( name ) @app . route ( "/vapi/webhook" , methods = [ "POST" ] ) def vapi_webhook ( ) : data = request . json message = data . get ( "message" , { } ) msg_type = message . get ( "type" ) if msg_type == "assistant-request" : return jsonify ( { "assistant" : { "name" : "Dynamic Assistant" , "firstMessage" : "Hello! How can I help?" , "model" : { "provider" : "openai" , "model" : "gpt-4.1" , "messages" : [ { "role" : "system" , "content" : "You are a helpful assistant." } ] , } , "voice" : { "provider" : "vapi" , "voiceId" : "Elliot" } , "transcriber" : { "provider" : "deepgram" , "model" : "nova-3" , "language" : "en" } , } } ) elif msg_type == "tool-calls" : results = [ ] for tool_call in message . get ( "toolCallList" , [ ] ) : results . append ( { "toolCallId" : tool_call [ "id" ] , "result" : f"Handled { tool_call [ 'name' ] } " , } ) return jsonify ( { "results" : results } ) elif msg_type == "end-of-call-report" : print ( f"Call ended: { message [ 'call' ] [ 'id' ] } " ) print ( f"Summary: { message . get ( 'summary' ) } " ) return jsonify ( { } ) if name == "main" : app . run ( port = 3000 ) Webhook Authentication Verify webhook authenticity using the secret: function verifyWebhook ( req : express . Request , secret : string ) : boolean { const signature = req . headers [ "x-vapi-signature" ] as string ; if ( ! signature || ! secret ) return false ; const payload = JSON . stringify ( req . body ) ; const expected = crypto . createHmac ( "sha256" , secret ) . update ( payload ) . digest ( "hex" ) ; return crypto . timingSafeEqual ( Buffer . from ( signature ) , Buffer . from ( expected ) ) ; } Local Development Use the Vapi CLI to forward webhooks to your local server:

Install the CLI

curl -sSL https://vapi.ai/install.sh | bash

Forward events to local server

vapi listen --forward-to localhost:3000/vapi/webhook Or use ngrok: ngrok http 3000

Copy the ngrok URL and set it as your server URL

End-of-Call Report Fields The end-of-call-report event includes: Field Description call Full call object with metadata transcript Complete conversation transcript summary AI-generated call summary recordingUrl URL to the call recording durationSeconds Call duration cost Total call cost costBreakdown Breakdown by component (STT, LLM, TTS, transport) messages Array of all conversation messages References Server URL Events — All event types with payload schemas Vapi Server URL Docs — Official documentation Local Development — Testing webhooks locally 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.