This is a writeup of how I built and launched a small API hub — what worked, what didn't, and the tech stack behind it. The Problem As developers, we use the same tools over and over: prompt optimization, JSON validation, text analysis. These are small, repeatable tasks that don't need a full SaaS — they just need a reliable API endpoint. The Stack Runtime: Python FastAPI in a Docker container Host: Raspberry Pi 4 (8GB) in my garage Tunnel: Cloudflare Tunnel (zero open ports on router)...