spina: Fix your posture while you work. Privately, on-device.

Hey Product Hunt 👋 I'm a solo dev who spent the last year hunched over Claude Code shipping side projects. My back finally said enough. I tried every "sit up straight" reminder app — they're all either annoying timers that have nothing to do with how I'm actually sitting, or web apps that want my camera feed in a browser tab forever. So I built Spina. It lives in your menu bar, watches your posture through the webcam at 2 FPS, and nudges you when you slouch. Everything runs on-device via MediaPipe — no video is recorded, no frames leave your Mac, no account needed. A few things I'm proud of: - Mirror Mode — see yourself with posture overlay when you want feedback - Calibration to your specific desk setup, not some generic ideal - Weighted scoring across 4 metrics with hysteresis, so it doesn't false-positive every time you turn your head It's a one-time purchase (no subscription nonsense for a menu bar app). Would love feedback from anyone who codes/designs all day. What would make this a daily-use tool for you? AMA below.