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Broadcast API for developers.

Add contacts, manage lists, and send texts, voice broadcasts, and ringless voicemail from your own software, then check delivery. A REST API with an OpenAPI 3.1 spec, scoped personal access tokens, and a 14-day free trial.

Start a free trialAPI reference

Included on the $99 a month plan · Usable during the 14-day free trial

Everything you need to build.

API reference

Every endpoint with its request and response schemas. Paste a token and send test requests.

OpenAPI spec

The OpenAPI 3.1 JSON for code generators, API clients, and AI agents.

Getting started guide

Create a token and send your first request, step by step, in the help center.

Get an API token in four steps.

  1. 01

    Start a free trial

    Sign up for the 14-day free trial. It includes 25 credits, a test number, and a demo keyword. A card is required.

  2. 02

    Create a personal access token

    An organization owner creates a token in API settings and picks its scopes: contact:read, contact:write, message:read, or message:write. The secret is shown once.

  3. 03

    Send a test text

    Send an SMS from a number on your account to your own phone with POST /api/public/v1/message/sms.

  4. 04

    Check delivery

    The send returns Queued. Poll GET /api/public/v1/message/{id} until the status is final, such as Delivered, Sent, Failed, or Skipped.

Quickstart

Send every request to https://api.callloop.com with Authorization: Bearer pat_v1.<token>. The pat_v1. prefix is required. Use E.164 phone numbers, and a fromNumber that belongs to your account.

Send a text

curl -X POST https://api.callloop.com/api/public/v1/message/sms \
  -H "Authorization: Bearer pat_v1.$BROADCAST_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "fromNumber": "+15555550100",
    "toNumber": "+15555550123",
    "smsMessage": { "text": "Hello from the Broadcast API" }
  }'

The response is HTTP 200 with state.status set to Queued: accepted for sending, not yet delivered. Keep its id.

Check delivery

curl https://api.callloop.com/api/public/v1/message/<id> \
  -H "Authorization: Bearer pat_v1.$BROADCAST_TOKEN"

Repeat until the status is final. Voice calls and ringless voicemail use /message/voice and /message/ringless with an audio ID that already exists in your account.

What the API covers.

Contacts

Create, look up, and update contacts. Requires a personal access token with contact:read or contact:write. 23 operations.

Assets

Upload and manage assets. 3 operations.

Contact cards

Create and manage contact cards. 4 operations.

Lists

Create and manage contact lists. 7 operations.

Messages

Send SMS, voice, and ringless voicemail, then poll for delivery. Requires a personal access token with message:read or message:write. 5 operations.

Audio

Upload and manage audio. 6 operations.

Good to know before you build.

Sending is asynchronous. A send returns Queued, which means accepted, not delivered. Poll the message with its numeric id or state UUID for the final status.

Use E.164 phone numbers, such as +15551234567. National US numbers without a country code are accepted. An invalid fromNumber or toNumber returns HTTP 400 naming the field.

The gateway may return HTTP 429 when your organization exceeds its request quota, and texts from one number may be throttled to about 2 a second. Retry with backoff.

Audio, asset, and contact card IDs must already exist in your account. Send endpoints do not accept file uploads; upload audio and assets first.

List endpoints are paginated the same way: page (zero-based), size (default 20; contacts allow up to 250), and sort as property,asc or property,desc. Each returns content, pageNumber, pageSize, and total.

The API is versioned in the URL: every path starts with /api/public/v1.

FAQ

Good questions. Clear answers.

Can’t find what you’re looking for?

Talk to our team
Is there a free tier or a sandbox?

There is no free plan or separate sandbox. The 14-day free trial includes the API, 25 credits, a test number, and a demo keyword, so you can build and test your connection before you pay. A card is required.

How much does the API cost?

The API is included on the $99 a month plan, which comes with 2,500 credits each month. You can also use it during the 14-day free trial.

How do I get an API key?

An organization owner creates a personal access token in API settings. Pick only the scopes the connection needs, and store the secret: it is shown once.

Is there an SDK or a CLI?

Not at the moment. Generate a client in your language from the OpenAPI spec with any OpenAPI generator, or call the REST endpoints directly.

Do I need a developer to connect my tools?

For the API, yes. If your tools are on Zapier or HubSpot, our integrations connect them without code.

Build with Broadcast.

Start the 14-day free trial, create a token, and send your first text today.

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