Build with Threll
Integrate autonomous voice agents into your product. Use the REST API to start and inspect phone calls, and webhooks to react to call events in real time — from live transcripts to mid-call tool dispatch.
curl https://api.threll.io/v1/accounts/9c3e8f02-7a14-4b62-bc59-1d8e5fa3027b \
-H "x-api-key: $THRELL_API_KEY"const res = await fetch('https://api.threll.io/v1/accounts/9c3e8f02-7a14-4b62-bc59-1d8e5fa3027b', {
headers: { 'x-api-key': process.env.THRELL_API_KEY },
});
const account = await res.json();import os, requests
res = requests.get(
"https://api.threll.io/v1/accounts/9c3e8f02-7a14-4b62-bc59-1d8e5fa3027b",
headers={"x-api-key": os.environ["THRELL_API_KEY"]},
)
account = res.json()Guides
Step-by-step walkthroughs, from your first authenticated request to a complete two-way integration.
Getting Started
Get your API key, authenticate, and make your first request.
Start here →Working with the REST API
Start an outbound call, handle errors, and fetch transcripts and audio.
Read guide →How Webhooks Work
Receive call events in real time and verify request signatures.
Read guide →End-to-End: Outbound
Start calls and combine REST with webhooks into a complete workflow.
Read guide →End-to-End: Inbound
Identify callers, serve mid-call tools, and log results for calls you receive.
Read guide →Telephony & Phone Numbers
Transports, per-worker numbers, and Quick Connect forwarding.
Read guide →Scheduled Calls
Queue calls for later and understand dispatch timing.
Read guide →Connect AI Agents (MCP)
Let Claude or your own agent operate your workforce over MCP.
Read guide →API Reference
Complete reference for every endpoint, event, and payload.
REST API Reference
Accounts, workers, and phone calls — every endpoint with request and response samples.
Browse endpoints →Webhooks Reference
All call events, request headers, signature verification, delivery and retries.
Browse events →MCP Reference
OAuth 2.1 flow, protocol methods, scopes, and the full tool catalog.
Browse tools →Limits & Errors
Rate limits, webhook delivery guarantees, and the full error catalog.
Browse →How the pieces fit together
A typical integration uses both directions:
- REST API (you → Threll). Authenticate with your
x-api-keyand start outbound calls, list your workers, and fetch call results — transcripts, audio recordings, extracted dimensions, and next actions. - Webhooks (Threll → you). Subscribe an HTTPS endpoint and receive events as calls happen. Sync events expect a response (worker configuration, tool results); async events are fire-and-forget notifications (transcripts, status changes, call end).
- MCP (AI agents → Threll). Connect Claude or your own agent to the MCP server and it can manage workers, place confirmed calls, and search call history conversationally.
If you only need to start calls and read results afterwards, the REST API alone is enough. Add webhooks when you want live transcripts, lifecycle updates, or to let workers call into your own systems mid-conversation.