Most ERD tools were built for DBAs. Schemity is built for software engineers. 9 MB, offline-first, Git-native. Your ERDs live as plain JSON in your repo, commit, diff, and review like code. Drag fields to create relationships. Flexible lines with custom waypoints. Check constraints as first-class citizens. Compare ERD to live DB and generate the exact SQL diff. Supports PostgreSQL, MySQL, SQL Server, Supabase. No Electron. No JVM. No subscription.
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Maker
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👋 Hi Product Hunt, I'm Son, solo founder and software engineer with 15+ years building backend systems.
I built Schemity because every ERD tool I tried had the same problem: rigid, auto-routed lines you can't control. Your diagram ends up as a random web of connections that tells you nothing about your actual data model. I spent years tolerating this before deciding to fix it.
What makes Schemity different:
- Flexible relationship lines with custom waypoints: arrange diagrams the way you think, not the way the tool forces you.
- Drag fields to create relationships: 1:N, 1:1, N:N with auto junction tables and FK naming.
- Check constraints as first-class citizens: encode business rules that double as living documentation.
- Live DB sync: compares your ERD to a running database and generates the exact SQL diff. Reverse-engineer existing DBs too.
- Offline-first, 9 MB, no Electron, no JVM: opens instantly, works behind VPN and air-gapped.
- Git-native: plain JSON in your repo, diffs and reviews like any other file.
- Supports PostgreSQL (multi-schema), MySQL, SQL Server, and Supabase.
- Keyboard-driven: Keyboard-first design, shortcuts, multiple tabs, copy/paste between diagrams.
One-time purchase, no subscription. Free 2-week trial, no credit card needed.
I read every comment and would love your feedback. 🙏