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

Method	Path	Key	Description
POST	/v1/contacts	secret or publishable	Create (or upsert) a contact by email
GET	/v1/contacts	secret	List contacts, paginated
GET	/v1/contacts/:id	secret	Fetch a single contact
PATCH	/v1/contacts/:id	secret	Update a contact
DELETE	/v1/contacts/:id	secret	Delete a contact

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.

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