OpenTax
US federal tax engine as a single binary CLI built for AI agents; covers Form 1040 for 2025.
What it does
A single-binary command-line tax engine that takes form entries for a return and returns the Form 1040 lines for tax year 2025, with MeF rule checks and XML or PDF export, plus Claude Code skills to prepare and review a return. The README calls it a calculator for AI agents and developers, not a filing tool, with code written and maintained by AI agents. Dual AGPL v3 and commercial licence.
Where it fits on the map
Not on the map: for individual taxpayers.
The map places maintained projects for a company tax department or a tax authority, without a demo or paid-service flag. Everything else stays on the list with its label.
Similar projects
Of the same kind, for a shared jurisdiction or tax area. Not a ranking.
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- EUROMODThe EU tax-benefit microsimulation model, maintained by the Joint Research Centre.
- GETTSIMThe German Taxes and Transfers Simulator: a microsimulation model of German taxes and benefits.
- IRS Fact GraphKnowledge-graph rules engine that models the US Internal Revenue Code, the calculation core of Direct File.
Maintain this project?
Link to this page from your README, so readers find the facts, the notes and where it fits. The badge is a small SVG served from this site.
[](https://tax-oss.com/projects/filed-opentax/)