Close REST API

REST discovered

Details

URL: https://api.close.com/api/v1
Docs: https://developer.close.com/api/overview

Authentication

Close API key basic discovered Get credentials ↗

Authorization: Basic <credential>

In the Close app, open API settings and create or copy an API key. The REST API docs say to send the API key with HTTP Basic Auth, using the API key as the username and an empty password. The MCP docs show the same key can also be sent in the Close-API-Key header.

OAuth 2.0 oauth2 discovered

Authorization: Bearer <credential>

OAuth 2.0 — self-onboarding

Point your MCP client at the server URL and approve access in the browser. The server supports OAuth Dynamic Client Registration (RFC 7591), so the client registers itself automatically — no developer-portal app, client_id, or client_secret to create.