contactapi

An open-source API to save contacts. Send a POST with an email and any other JSON fields you want, and they get saved as-is. Manage them with simple CRUD.

Built with Hono and deployed on Vercel.

• Landing page & docs — /

• Log in — /login

• Sign up — /signup

• LLM-friendly docs — /llms.txt

API overview

The base URL is https://contactapi.dev and every request carries your API key as a Bearer token:

Authorization: Bearer YOUR_KEY

Contacts are keyed by email — creating one whose email already exists updates it in place rather than duplicating it. Full reference lives on the landing page and in /llms.txt.

There are two kinds of key:

• ck_secret_… — secret key, for your backend. Full access to every endpoint.

• ck_pub_… — publishable key, for the browser. Can only create contacts and is locked to your domains.

Related MCP server: MCP Google Contacts Server

MCP server

AI clients (Claude Desktop, claude.ai custom connectors, Cursor, the MCP Inspector) can manage your contacts through an MCP server at:

https://contactapi.dev/mcp

Auth is OAuth 2.1 with dynamic client registration — point a client at the URL and it discovers the authorization server, registers itself, and sends you to log in and approve access; no API key to copy. The server exposes five tools that mirror the REST API: list_contacts, get_contact, create_contact (upsert-by-email), update_contact, and delete_contact. Everything is scoped to the account you log in as.

The OAuth provider is Better Auth's mcp plugin (src/auth.ts); the tools and endpoint wiring live in src/mcp/server.ts and src/index.ts.

Development

Prerequisites: Vercel CLI installed globally.

npm install
vc dev
open http://localhost:3000

Build

npm install
vc build

Deploy

npm install
vc deploy

License

MIT