How to Build MCP Gateway from Scratch This guide covers how to build MCP gateway from scratch - a production middleware layer that routes, authenticates, rate-limits, and observably forwards AI agent tool calls. Covers TypeScript code, architecture decisions, and hardening for multi-tenant deployments. An MCP gateway is a middleware layer that sits between AI agents and the external tools, data sources, and services they need. It handles routing, authentication, rate limiting, protocol tr...