---
title: "Extension points"
description: "Ways to connect your app to OnePageCRM — the platform APIs, and the lightweight extension points that need no full integration."
canonical_url: https://developer.onepagecrm.com/integrations/overview/
source: Markdown mirror of https://developer.onepagecrm.com/integrations/overview/
---

OnePageCRM connects to many tools out of the box, and you can build your
own integration on top of its API, webhooks, and MCP server.

## Platform APIs

Full programmatic access to the CRM:

- **[REST API](/api/reference/)** — create, read, and update contacts,
  companies, deals, actions, notes, calls, and meetings. Authenticate
  with an [API key](/api/authentication/) for your own account, or
  [OAuth 2.1](/oauth/overview/) for an app acting on behalf of other
  OnePageCRM users.
- **[Webhooks](/webhooks/overview/)** — get notified the moment a record
  changes, so you sync in real time instead of polling.
- **[MCP server](/mcp/overview/)** — let AI agents read, write, and
  [query](/oql/overview/) the CRM over the Model Context Protocol.

## Lightweight extension points

Purpose-built ways to connect without a full integration:

- **[External ID](/integrations/external-id/)** — store your own stable
  identifier against contacts, companies, and deals so you can sync
  between systems without a separate lookup table.
- **[Custom Button](/integrations/custom-button/)** *(beta)* — place a
  contextual action button in the OnePageCRM UI that opens your app with
  record context as parameters.
- **[Create a contact via URL](/integrations/quick-create-contact-url/)** —
  the lowest-friction option: a link that opens OnePageCRM with the Add
  Contact form pre-filled. Great for "Save to OnePageCRM" buttons in your
  own app.

## Prebuilt connectors

For no-code integrations, browse the
[OnePageCRM marketplace](https://www.onepagecrm.com/marketplace/) — 40+
prebuilt connectors for tools like Gmail, Mailchimp, Xero, and QuickBooks.