ZeroReach developer docs
Build on ZeroReach with the REST API, connect Zero to your AI tools over MCP, and learn exactly how each feature behaves.
Developer documentation
ZeroReach is a B2B AI revenue assistant. It researches leads, runs email sequences, handles replies and calls interested leads with a voice agent to qualify them and book meetings. Zero is its AI assistant.
Everything in these docs is written from the code. The API reference, the MCP tool reference, the scopes and the changelog are generated from it by npm run docs:sync.
Start here
Call the API in 5 minutes
Create an API key and make your first requests with curl, Python or TypeScript.
Connect Zero to Claude or Cursor
Use the MCP server from Claude, Cursor or any MCP client, with OAuth or an API key.
Authentication
API keys, OAuth for MCP, workspaces and roles.
Errors and limits
The
{"detail": ...} format, status codes and rate limits.Explore
Guides
Leads, campaigns, email, calls, deals, meetings and how the compliance gates work.
Zero & MCP
What Zero can do, every MCP tool and which actions stay human-only.
API reference
Every public endpoint with its parameters, request and response.
Changelog
What shipped, by date.
How the platform fits together
| Part | What it does |
|---|---|
| Core API (Rust) | Serves every public route under /api/v1, the MCP server at /api/v1/mcp, and the background jobs (sequences, webhooks, imports). |
| AI service (Python) | Research, email writing, reply handling, the knowledge base and other AI routes. The core forwards those routes to it, so you call one host. |
| Voice agent | A phone agent that qualifies leads and books meetings. It reports back through the /api/v1/calls/{call_id}/... routes. |
| Web app | The ZeroReach app, where people sign in, review drafts and approve sends. |
Compliance is enforced in code
Consent, suppression lists, calling windows and send caps are checked by the server before any outbound action, whatever the client: the app, the API, MCP or Zero. See Compliance.