Developers
This section is for developers building against Willow rather than configuring it in the dashboard. It covers authenticating to the gateway programmatically, calling MCP tools over HTTP, and building internal MCP servers that Willow proxies to.
Tutorials
Start here to build something end to end:
- Try the Willow API for free — create a free organization, generate a
wxt_API token, and make your first Admin API call without a sales call. Also covers test environments and generating a client from the OpenAPI specs. - Make your first gateway call — create a machine user and make an authenticated MCP tool call from a script with
curl. - Build an OAuth MCP server with Express — a complete, runnable Node.js server for Proxy OAuth, connected in Willow end to end.
- Build an API-key MCP server with Express — a complete, runnable Node.js server for Proxy API Key.
Reference
- Programmatic gateway access — the
/mcpendpoint, machine-user auth, the MCP handshake, and tool namespacing. - API versioning and deprecation — the Admin API's current version, the
Willow-API-Versionheader, and how deprecations are announced with at least 6 months' notice. - Build an MCP server behind Willow — how Willow forwards auth per server auth mode, and how to validate the token you receive.
- Build an OAuth-protected MCP server — the discovery, registration, authorization, and token endpoints Willow's Proxy OAuth mode expects.
- Accept per-user API keys — receive and validate the key Willow forwards in Proxy API Key mode.
- How identities authenticate — how human and machine identities differ at the front door and downstream.
- User session authentication — how the stdio client mints an OTT, opens a sign-in URL, and polls until the user is bound.
- Willow Docs MCP server — search and read these docs from any AI tool, optionally scoped to admin guides, user guides, or the API reference.
- OAuth Authorization Server — the gateway's OAuth resource metadata and token endpoint.
- SCIM API — user and group provisioning endpoints.