MCP Server CORS: The Preflight Problem That Broke My MCP Server 92 Times And How I Fixed It For Good
Honestly, I thought I understood CORS. I've been building web apps for almost 10 years. How hard can it be?
Turns out, MCP changes everything.
After 92 production outages where my MCP server randomly failed with cryptic CORS errors that only happened in production but never locally, I finally figured out what was going on. And it's not what you think.
Let me save you the three days of debugging I went through.
