AI wrote the rules as code. The engine does the math.
yTax is a deterministic U.S. federal income-tax engine. The same inputs always give the same result, in exact dollars, and every value can be traced to the rule and facts it depends on.
Explore the federal tax-year 2025 alpha on Windows or macOS. Try the included example households, follow the document-to-form workflow, and help shape what comes next.
Alpha preview for evaluation with example data. Not for preparing or filing an actual tax return.
See the rules behind the results.
Tax rules should be easier to examine, discuss and improve. yTax's rules live in a readable dictionary, written in a declarative language represented in XML, so tax experts can read and question them without knowing a general-purpose programming language. It is built on Fact Graph, the technology behind IRS Direct File, which connects inputs and rules so every value can be traced to what it depends on.
The public source release, ytax-facts alpha-0.1.0, carries the federal tax-rule dictionary, the calculation engine, the XML-to-JavaScript dictionary generator, printed-form field maps and the ytax-prep application source. Fact Graph and Direct File tells the story behind it.
From documents to filled forms.
ytax-prep reads supported tax documents, asks only for the information they do not give, and fills supported IRS forms for a 2025 federal return. Ready-to-run packages are available for Windows and macOS, with made-up households to explore the whole workflow. Releases has the downloads.
Local-first by design.
ytax-prep works in a folder you choose, and processing stays on your computer by default. An optional check by an AI model can read the pages a second time; Privacy explains how it works.
Built carefully. Tested from several angles.
AI writes the rules as code, and independent AI agents test and verify the results. Our development process combines automated regression testing, source-based review, separately implemented calculations and comparisons with other tax engines.
We also test the journey from documents and answers to calculated results and filled forms. Findings lead to corrections, new test cases and separate rechecks, turning review into practical improvements.
A foundation with room to grow.
Our goal is complete coverage of U.S. federal and state personal income taxes, with a calculation foundation that can serve people directly and support other software.
The federal alpha is the starting point. Planned work includes additional federal situations, the next tax year and state returns. Tax expertise, thoughtful testing and practical feedback can help shape that progress.