MCP or API key?

Both reach the same tools with the same permissions. The right one depends on who's doing the talking.

You're…	Use	Start here
Chatting with Claude, ChatGPT, Claude Code, or Cursor	MCP connector — paste the URL, sign in	Connect Claude, Connect ChatGPT, Other MCP clients
Using an MCP client with no sign-in, only a headers field	MCP endpoint + API key	Other MCP clients
Writing a script, a backend, or a Zapier-style automation	REST API + API key	API Quickstart

MCP is for an assistant acting on your behalf in a conversation. Sign-in is a browser flow, the token is short-lived and renews itself, and the assistant acts as you in one workspace. There's nothing to copy or store.

An API key is for code. It's a long-lived secret you keep in an environment variable, scoped to one workspace and to either read or write. Anything that runs without a person present — a nightly sync, a webhook handler, a CI job — wants a key.

If you're not sure, you want MCP. Anyone who needs a key already knows it.

The MCP server is included on Essential plans and up, and the REST API on Pro and up. The Authentication guide covers scopes and errors in depth.