Show HN: Cross-region network routing of websockets with Fly.io's built-in proxy (github.com)

Hi, I've recently had a chance to dig into using Fly.io's builtin proxy[^1] for cross-region network routing of HTTP calls and websockets.

This is especially useful if you're building collaborative experiences at the edge, such as a real-time chat, a multiplayer game, or a Figmadobe competitor (wink wink).

The demo works: https://fly-replay-header-demo.fly.dev/ -- the country flag visually confirms which instance you're connected to.

That being said, I made a couple fun mistakes along the way, so I figured I'd write up and share what I've learned. Suggestions for improvement are also welcome. Cheers!

[^1] https://fly.io/docs/reference/architecture/#fly-networking