I Built MCP Servers for 9 SaaS APIs — Here's What I Learned About the Pattern

I Built MCP Servers for 9 SaaS APIs — Here's What I Learned About the Pattern

I've spent the last few weeks building MCP (Model Context Protocol) servers for various APIs — CoinGecko, Stripe, Jira, PostHog, Plausible, Etherscan, DeFiLlama, Jobber, and Resend. Nine servers, 68 tools, all published to npm and indexed on Glama.

Along the way, I noticed the same architecture keeps working. If you're building an MCP server for your own API — or thinking about hiring someone to do it — here's the pattern.

The Three-Layer Architecture

Every MCP server I build has three layers: