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Quoting Craig Mod

Simon Willison's Blog / 3/14/2026

💬 OpinionTools & Practical Usage

Key Points

  • The quoted passage describes building a personal accounting tool that is faster, completely local, multi-currency, and capable of ingesting CSV data and presenting it in a dashboard.
  • It notes the tool learns from categorizing expenses, handles US and Japan tax rules, processes 1099s and K-1s, and can import PDFs for accountants.
  • It mentions reconciliation of international wire transfers with FX-rate variations and the ability to talk directly with Claude to brainstorm batched solutions and implement small feature tweaks.
  • The author describes the software as organic and pliable, shaped to the user's data and workflow.

13th March 2026

Simply put: It’s a big mess, and no off-the-shelf accounting software does what I need. So after years of pain, I finally sat down last week and started to build my own. It took me about five days. I am now using the best piece of accounting software I’ve ever used. It’s blazing fast. Entirely local. Handles multiple currencies and pulls daily (historical) conversion rates. It’s able to ingest any CSV I throw at it and represent it in my dashboard as needed. It knows US and Japan tax requirements, and formats my expenses and medical bills appropriately for my accountants. I feed it past returns to learn from. I dump 1099s and K1s and PDFs from hospitals into it, and it categorizes and organizes and packages them all as needed. It reconciles international wire transfers, taking into account small variations in FX rates and time for the transfers to complete. It learns as I categorize expenses and categorizes automatically going forward. It’s easy to do spot checks on data. If I find an anomaly, I can talk directly to Claude and have us brainstorm a batched solution, often saving me from having to manually modify hundreds of entries. And often resulting in a new, small, feature tweak. The software feels organic and pliable in a form perfectly shaped to my hand, able to conform to any hunk of data I throw at it. It feels like bushwhacking with a lightsaber.

Craig Mod, Software Bonkers

Posted 13th March 2026 at 5:14 pm