LineHQ for developers

LineHQ answers your business calls. With its Public API, webhooks and MCP server, your own systems can use what happens on those calls: who rang, what they wanted and what to do next.

What you can build

Call logging in your own tools. Pull every call, with its AI summary, transcript and recording, into a CRM, helpdesk or spreadsheet LineHQ doesn't connect to.
Caller names from your records. Keep LineHQ's contact directory in step with your own system, so calls and notifications name the caller.
Follow-ups that start themselves. React the moment a call ends, a voicemail arrives or a transcript is ready.
Your own reporting. Read call totals, the prepaid balance and receipts for your dashboards and accounts.

Ways in

Public API

Read the account, its numbers, calls, transcripts, text messages and inbox, and keep its contacts in step. Read the API reference, or download openapi.json for Postman, a code generator or an AI agent.

Webhooks

LineHQ posts call.ended, voicemail.received and transcript.ready events to your HTTPS endpoint, each signed so you can check it came from LineHQ. Add endpoints on the Integrations page in the LineHQ portal, or through the API.

MCP

An AI assistant such as Claude or ChatGPT can connect to a LineHQ account at https://linehq.co.uk/mcp/account, signing in with the account's own LineHQ login, to answer questions about it and make safe changes. How to connect an AI assistant.

Guides

Authentication: How to call the LineHQ Public API: API keys and their permissions, account roles, rate limits, errors, ids and pagination.
API reference: Every LineHQ Public API endpoint: what it does, the API key permission it needs, its parameters, examples in curl, JavaScript and Python, and an example response.
Webhooks: Receive LineHQ call events at your own HTTPS endpoint: the events, headers, signature check, retries and an example of each payload.
Connect an AI assistant (MCP): Connect Claude or ChatGPT to a LineHQ account over MCP: how to connect, what it can and can't do, and what it costs.
Changelog: What has changed in the LineHQ Public API, with dates, and the promise about breaking changes.

Get started

Get an API key. The account owner, or a member the owner allows, creates one in the LineHQ portal. Give it only the permissions your integration needs.
Make your first request. Send the key in the Authorization header of every request:
```
curl "https://app.linehq.co.uk/api/v1/me" -H "Authorization: Bearer $LINEHQ_API_KEY" -H "Accept: application/json"
```
It answers with the account and user the key belongs to, and the permissions the key holds.
Build against the reference. Every documented endpoint is tested against its documentation before each release.

Raw data, or CRM Sync?

The API gives you raw data: calls, summaries, contacts and events, to use however you like. CRM Sync is LineHQ's managed alternative for supported CRMs: it matches each caller to a contact, creates contacts and writes a formatted note for every call, with nothing for you to build or keep running. If your CRM is supported, CRM Sync is usually the quicker route.

This page as Markdown, for AI tools: https://linehq.co.uk/developers.md