Remote MCP server starter for Railway

A Model Context Protocol server your agent connects to over the network, with a working OAuth 2.1 authorization server in front of it. Deploy it, add the URL to your client, type a password once — the client registers itself and gets a token.

Why this exists

The catalogue has plenty of MCP servers, and almost all of them wrap somebody else's SaaS: a server for Whoop, one for Meta Ads, one for a CRM. If what you want is to expose your own data — an internal API, a database, a document store — there is nothing to start from.

The hard part was never the tools. It is everything around them:

• Transport. Streamable HTTP replaced SSE, and stateless is the shape that survives more than one replica. Sessions in memory mean sticky routing.

• Authorization. The MCP spec puts OAuth 2.1 in the required path: PKCE, dynamic client registration, protected-resource metadata under RFC 9728, resource indicators under RFC 8707. Clients will not connect without it.

• Storage. Codes and tokens have to outlive the process that issued them, or every deploy logs everyone out and a second replica rejects the first one's tokens.

This starter does all three, and leaves you three example tools to replace.

Related MCP server: MCP Auth

What you get

Three example tools — add_note, search_notes, whoami — are backed by a real table. They exist so a fresh deployment can be proven end to end, and so you have a working handler to copy.

Deploy

Two services: this repository and a Postgres. The template wires them together and generates the password for you.

After the first deploy, open the service URL — the page shows the exact URL to paste into your client.

Add it to a client

Use https://<your-domain>/mcp. The client discovers the authorization server, registers itself, opens the login page in a browser, and stores the token it gets back. There is nothing to configure on the client side and no API key to copy around.

For clients that speak stdio only, npx mcp-remote https://<your-domain>/mcp bridges the two.

Prove it works

npx tsx scripts/verify-oauth-flow.ts https://<your-domain> '<the password>'

The script walks the whole path a real client walks — discovery, registration, PKCE, login, token exchange, tools/call — and also checks the parts that are supposed to fail: an unauthenticated call, a wrong password, a replayed authorization code.

Write your own tools

src/tools.ts is the whole surface. Add a registerTool call with a Zod input schema and a handler; the token that authorized the call arrives as auth, so you can key data by auth.clientId or check auth.scopes per tool.

The example tools are deliberately backed by Postgres rather than returning canned strings — that is what makes a first deploy prove the write path.

How the security is set up

• Tokens are stored hashed (SHA-256). A database dump does not hand anyone a working token.

• Authorization codes are single-use, enforced by marking them consumed in the same statement that reads them, so a replay finds nothing to update — not by a check-then-write that two concurrent requests can both pass.

• PKCE is required (S256); the code challenge is bound to the code.

• Login is rate limited — 10 attempts per address per 15 minutes, counted in Postgres so the limit holds across replicas rather than per process.

• Passwords are compared in constant time, over hashes, so neither content nor length leaks through timing.

• Refresh rotates: using a refresh token revokes it and issues a new pair. A refresh can narrow its scopes, never widen them.

One honest note: client secrets issued by dynamic registration are stored as issued, because the SDK's client authentication compares them directly. MCP clients normally register as public clients and rely on PKCE, which is the path this server expects.

Configuration

Run locally

npm ci
cp .env.example .env
npm run dev

The SDK refuses a plain-HTTP issuer except on localhost, which is exactly where you will be running it.

Using an external identity provider

This server is its own authorization server, which is what makes it deploy in one click. If you already run Keycloak, Auth0 or Zitadel, replace mcpAuthRouter with mcpAuthMetadataRouter and point it at your issuer; the tools and transport stay as they are.

A note on versions

Built on @modelcontextprotocol/sdk 1.29.0, the current stable line. The v2 SDK splits into @modelcontextprotocol/server and friends and is still in beta at the time of writing; this starter will move when it stabilises.

License

MIT