Introduction

Already on V2?

Migrate to V3 and unlock delivery receipts, trace IDs, message effects, custom reactions, and more. See the V2 → V3 migration guide.

The Linq Partner API is a RESTful API at https://api.linqapp.com/api/partner/v3 that provides programmatic access to iMessage, RCS, and SMS messaging infrastructure.

New to Linq? Start with the Quickstart to send your first message in under 5 minutes, or explore the API Reference for the complete endpoint specification.

Prerequisites

To use the Linq Partner API, you’ll need:

• A bearer token provisioned by your Linq representative
• One or more phone numbers assigned to your account
• An endpoint URL for receiving webhooks (optional but recommended)

For step-by-step setup, see Quickstart.

What you can build

The Linq Partner API supports a wide range of messaging use cases:

• Customer support — Route conversations, send rich media, and integrate with your support stack
• Sales engagement — Personalized outreach with read receipts and delivery tracking
• Appointment reminders — Automated notifications with confirmation workflows
• Order notifications — Shipping updates, delivery confirmations, and feedback collection
• AI-powered agents — Build conversational AI that communicates over iMessage, RCS, and SMS

See open-source examples for real-world implementations.

Key capabilities

Feature	Description
Unified messaging	Send via iMessage, RCS, or SMS from a single API with automatic or explicit protocol selection
Rich media	Share images, videos, documents, voice memos, and contact cards up to 100MB
Group chats	Create and manage group conversations with participant controls
Message threading	Reply to specific messages within a conversation
Reactions	Add built-in tapbacks or any custom Unicode emoji to messages
Message effects	Confetti, fireworks, slam, gentle, invisible ink, and more (iMessage)
Typing indicators	Show and receive real-time typing status
Real-time webhooks	Instant notifications for delivery, read receipts, reactions, and incoming messages
Built-in debugging	W3C trace IDs on every request for end-to-end observability

Authentication

All requests require a bearer token in the Authorization header:

Authorization: Bearer YOUR_TOKEN

For details on token management and security best practices, see Authentication.

Quick example

Send a message with a single API call:

curl -X POST https://api.linqapp.com/api/partner/v3/chats \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "+12223334444",
    "to": ["+15556667777"],
    "message": {
      "parts": [
        { "type": "text", "value": "Hello from Linq!" }
      ]
    }
  }'

Handle formats

• Phone numbers must be in E.164 format: +12223334444
• Email addresses use standard format: [email protected]
• No spaces, dashes, or parentheses in phone numbers

Next steps

Quickstart

Send your first message in under 5 minutes. Get started →

Sending Messages

Text, media, threading, effects, and protocol selection. Learn more →

Webhooks

Real-time event notifications with signature verification. Set up webhooks →

API Reference

Complete endpoint specification with request and response schemas. View reference →

Client SDKs

Official TypeScript and Python SDKs with type safety and automatic retries. Install SDKs →

Error Codes

Complete error reference with troubleshooting guidance. View errors →