Show HN: I rewrote my notepad calculator as a local-first app with CRDT syncing

6 tonyonodi 1 6/30/2025, 8:10:27 AM numpad.io ↗

I launched NumPad v1 on here a few years ago, and back then it wasn't much more than a thin CodeMirror wrapper around the calculator engine I'd written.

Now I've rewritten it as a PWA that supports multiple documents, persists them to IndexedDB, and has a syncing service for paying customers. Syncing is handled by Automerge[1] under the hood, which should make it relatively easy to get document sharing working too.

[1] https://automerge.org/

Comments (1)

johncosta27 · 4h ago

This is very cool. I was able to so some a small budget to see what my expenses are monthly, it's quite nice. I can see myself using it anytime I need something more than paper, and less than a full spreadsheet. Very cool.

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Show HN: I rewrote my notepad calculator as a local-first app with CRDT syncing

Comments (1)