Developer Platform

CRM with MCP and its own Query Language. Agents welcome.

OQL queries the whole CRM in one request. MCP gives your agent live read and write access. REST and webhooks for everything else.

Start building API reference

We can't wait to see what you build.

Build integrations

Wire OnePageCRM into the rest of your stack — sync contacts, automate follow-ups, push deals into your data warehouse.

Automate workflows

React to CRM events the moment they happen — webhooks for contacts, companies, deals, actions, notes, calls, and meetings.

Connect AI agents

Query and update CRM data from agents and copilots via OQL and the MCP server. Real-time, structured access.

Try it

One curl call from your first contact.

HTTP Basic auth, JSON in, JSON out. Everything's documented in the OpenAPI spec, and the API reference gives you copy-ready curl for every endpoint.

Request curl

$ curl -u "USER_ID:API_KEY" \
    https://app.onepagecrm.com/api/v3/contacts.json

Response 200 OK

{
  "status": 0,
  "message": "OK",
  "data": {
    "contacts": [
      { "contact": { "id": "5f…", "first_name": "Ada" } }
    ],
    "total_count": 42
  }
}

Need a token for users who aren't you? Use OAuth 2.1 →

Read & write CRM data

A REST API for contacts, companies, deals, actions, notes, calls, and meetings.

API reference

React to changes in real time

Subscribe to webhooks for created, updated, and deleted events on every resource — plus action completions and deal status changes.

Webhooks reference

Authorize third-party apps

Request access

OAuth 2.1 lets your app act on behalf of a OnePageCRM user with the right scopes — authorization-code flow with PKCE and rotating refresh tokens.

OAuth concepts

Build with AI

Agent-readable docs for your AI coding assistant, and a live MCP server that lets AI agents query and update the CRM.

Build with AI

Ask questions of your data

OQL is a JSON query language over all seven core entities — filters, lookups, aggregates, and grouping, instead of paging everything down. It runs through the MCP server.

OQL overview

Connect without a full integration

Map records to your own system with External ID, add a Custom Button to the contact and deal menus, or pre-fill the Add Contact form from a link.

Extension points

Built for agents

Docs your AI assistant can actually read.

Every documentation page on this site is published as clean markdown, indexed in llms.txt and described in agents.json — so your coding assistant works from real endpoints and real field names.

Agents that need live data connect to the MCP server and query or update the CRM through the Model Context Protocol.

Build with AI Read llms.txt

Any docs page html

/webhooks/payloads/

Append .md markdown

/webhooks/payloads.md

---
title: "Payloads"
canonical_url: …/webhooks/payloads/
---
…raw markdown, no nav, no chrome

Learn by doing

Featured tutorials

All tutorials

🚀

Make your first API call

Authenticate, list your contacts, and parse the response in under five minutes.

Read

📡

Subscribe to webhook events

React to CRM changes in real time. Register a webhook, receive a payload, and respond correctly.

Read

🔍

Query CRM data with OQL

Use OQL to read contacts, deals, actions, and notes with filters, aggregates, and date helpers.

Read

All tutorials