Is there an OpenAPI specification available?

Yes. The full OpenAPI 3.0 spec is available at api.teloz.com/openapi.json and can be imported directly into Postman, Insomnia, or any compatible client. It is kept in sync with every release.

What authentication method does the API use?

The API uses Bearer token authentication. Pass your API key in the Authorization header as 'Bearer YOUR_API_KEY'. For server-to-server use we recommend scoped keys; for browser-embedded dialers use OAuth short-lived tokens.

Are there rate limits?

Yes — the default limit is 100 requests per second per API key. Bursts up to 500 req/s are allowed for up to 10 seconds. Enterprise plans can request higher limits. Rate limit headers (X-RateLimit-Remaining, X-RateLimit-Reset) are returned on every response.

How do I verify webhook signatures?

Every webhook POST includes an X-Teloz-Signature header containing an HMAC-SHA256 hash of the raw request body signed with your webhook secret. Compute the same hash on your end and compare — reject requests that don't match.

Is there a sandbox environment for testing?

Yes. Use the base URL https://api.sandbox.teloz.com with your test API key. Calls made in sandbox mode are never connected to the PSTN — they simulate the full event lifecycle including recordings and transcripts.

Teloz REST API

Build voice into anything with the Teloz API

Q: How do I get an API key?

Sign up for a Teloz account and navigate to Settings → Developer → API Keys. You can create multiple keys with scoped permissions (read-only, calls-only, admin) and revoke them at any time.

Initiate calls, receive webhooks, stream transcripts, and embed a full-featured dialer — all through a clean REST API with SDKs for every major language.

Start a Free Trial Documentation hub

REST APIWebhooksOpenAPI SpecSDKs99.99% Uptime

200 OK — call queued

OpenAPI 3.0 spec included

teloz-api.js

// Initiate an outbound call
 
const response = await teloz.calls.create({
  to: "+12025550123",
  from: "+18005550199",
  record: true,
  webhook: "https://your-app.com/events"
});
 
// Response
// {
//   sid: "CA3f9a…"
//   status: "queued"
//   duration: null
// }

By the Numbers

Built for production from day one

The Teloz API is the same infrastructure powering thousands of US business phone systems every day.

99.99%

API uptime SLA

Enterprise-grade reliability

< 100ms

Median response time

Across all US regions

50+

REST endpoints

Calls, contacts, numbers & more

4 SDKs

Official language libraries

Node, Python, PHP, Go

Endpoints

Six resource groups, 50+ endpoints

Everything you need to build voice, SMS, and contact centre features into your product.

POST · GET · DELETE

Calls

Initiate outbound calls, retrieve call records, access recordings, and stream real-time transcripts.

POST/v1/calls

GET/v1/calls/:sid

GET/v1/calls/:sid/recording

DELETE/v1/calls/:sid

POST · GET · PUT · DELETE

Contacts

Create, read, update, and delete contacts. Sync with your CRM or build your own phonebook.

POST/v1/contacts

GET/v1/contacts

PUT/v1/contacts/:id

DELETE/v1/contacts/:id

POST · GET · DELETE

Numbers

Search available numbers, provision local or toll-free DIDs, and manage number configuration.

GET/v1/numbers/available

POST/v1/numbers

GET/v1/numbers/:id

DELETE/v1/numbers/:id

POST · GET · DELETE

Webhooks

POST/v1/webhooks

GET/v1/webhooks

PUT/v1/webhooks/:id

DELETE/v1/webhooks/:id

GET

Analytics

Pull call volume, duration, disposition, and queue stats for your dashboards and reports.

GET/v1/analytics/calls

GET/v1/analytics/queues

GET/v1/analytics/agents

GET/v1/analytics/summary

JavaScript SDK

Embedded Dialer

Drop a full-featured click-to-call widget into any web app with a few lines of JavaScript.

teloz.dialer.init(config)

teloz.dialer.call(number)

teloz.dialer.on('event', fn)

teloz.dialer.destroy()

Code Examples

Integrate in your language of choice

Official SDKs for Node.js, Python, PHP, and Go — or call the REST API directly from any language.

Initiate a call

import Teloz from "@teloz/node";
 
const client = new Teloz(process.env.TELOZ_API_KEY);
 
const call = await client.calls.create({
  to: "+12025550123",
  from: "+18005550199",
  record: true,
  transcribe: true,
  webhook: "https://your-app.com/events",
});
 
console.log(call.sid); // CA3f9a7b…

Webhooks

React to every call event in real time

Register a webhook URL and Teloz will POST a signed JSON payload to your endpoint the moment an event occurs — no polling required. Combine webhooks with our integrations to automate your workflows end-to-end.

HMAC-SHA256 signature on every payload

Automatic retry with exponential backoff

Delivery logs & replay in the dashboard

Filterable by event type per endpoint

EventCategory

call.initiatedFired when an outbound call is queued

Calls

call.ringingThe destination phone is ringing

Calls

call.answeredCall was picked up — includes caller metadata

Calls

call.completedCall ended — includes duration, disposition

Calls

call.missedInbound call went unanswered

Calls

recording.readyRecording file URL is available for download

Recording

transcript.readyFull transcript text and speaker labels attached

voicemail.newNew voicemail received with audio URL

Voicemail

sms.inboundInbound SMS received on a provisioned number

SMS

API FAQs

The short answers.

Common questions before you start building.

Sign up for a Teloz account and navigate to Settings → Developer → API Keys. You can create multiple keys with scoped permissions (read-only, calls-only, admin) and revoke them at any time.

Start building with the Teloz API. Free sandbox included.

Get your API key in under two minutes. Test with our full-featured sandbox before going live — no credit card required.

Get API Key View Docs

Full OpenAPI spec4 official SDKsSandbox environmentUS developer support