Multitrax Song Collab App
Feb 28, 2026 • 1 min read
A side project born from a group chat, some expiring credits, and an excuse to experiment with Agentic Engineering, GPT-5.3 Codex, Flutter, and Supabase.
A few weeks ago, a group chat with a few friends popped up about collaborating on a song together. The itch to experiment with Agentic Engineering and GPT-5.3 Codex was way too strong to ignore—and I had some unused credits that were about to expire anyway.
I’ve also been wanting to spend more time experimenting with Supabase, so this felt like the perfect excuse to scratch both itches at once.
Enter Multitrax: a Flutter + self-hosted Supabase MVP for async multitrack recording and collaboration. It’s very much a work in progress, but already a fun playground for ideas I’ve been wanting to explore.
You can check out here: Multitrax.