Developers

Source

The public API lets external tools work with Custom One programmatically: build and publish a custom, create and enrich leads in it, read its columns, and subscribe to lead-journey events (webhooks). It is the same API an AI assistant works through, and the one an automation platform such as Make, Zapier or n8n uses with a key.

Authenticate every request with a workspace API key. Create one under Integrations, on the AI assistants or Automations tab — see API keys and permissions. The key prefix selects the environment: co_live_… targets production, co_test_… targets development.

API reference — every endpoint, request and response, and a link to the machine-readable OpenAPI document.
AI assistants (MCP) — connect Claude, ChatGPT or another assistant to a workspace, with no key to copy (tools configured by file, like Cursor, take a key).