Express.js MCP OAuth Authentication with Scalekit

Overview

This skill documents the pattern for building production-ready MCP (Model Context Protocol) servers using Express.js, TypeScript, and OAuth 2.1 Bearer token authentication via Scalekit. This approach provides fine-grained control over HTTP request handling, middleware chains, and server behavior for Node.js-based MCP implementations.

When to Use This Pattern

Use this Express.js MCP integration when you need:

• Node.js ecosystem: Leverage existing npm packages, TypeScript tooling, and JavaScript libraries
• Custom middleware chains: Implement rate limiting, request logging, or complex authorization logic with Express middleware
• Existing Express applications: Add MCP capabilities to established Express.js codebases without rewriting
• Fine-grained HTTP control: Manage routing, CORS policies, health checks, and multiple endpoints
• Production flexibility: Deploy on serverless platforms (AWS Lambda, Vercel), containers, or traditional Node.js hosts

Don't use this pattern if you prefer Python's ecosystem or if a simpler MCP server setup (without Express) meets your requirements.

Core Architecture