Open source & free forever

Tax preparation that shows its work

Every number traces to IRS rules and your source documents. All computation runs in your browser — your data never leaves your device.

Standalone Web App

Clone, run, and file your taxes in your browser. No server, no account required.

OpenClaw Plugin

16 tool definitions, SSE streaming, and REST API for AI-powered tax agents.

Plugin Docs →
20+ IRS sources cited
10 validated scenarios
Full computation tracing
Zero data transmitted

Why OpenTax

Tax software should be transparent, private, and free. We built OpenTax to prove it's possible.

Free forever

No upsells, no paywalls. MIT-licensed, open-source. Every feature available to everyone.

Fully explainable

Every number traces back to source documents and IRS rules. Click any line to see exactly how it was computed.

Privacy-first

All computation runs in your browser. No server, no account, no tracking. Your tax data stays yours.

Audited correctness

Deterministic rules engine with 1,700+ tests cross-referenced against IRS publications. View Trust Center.

Two ways to use OpenTax

Run it standalone for personal filing, or integrate it into AI-powered tools as an OpenClaw plugin.

Standalone app

Clone the repo, run npm run dev, and file your taxes in your browser. Upload W-2s and 1099s, walk through a guided interview, and download IRS-ready PDFs.

  • Client-side only — zero data transmission
  • Full trace/explainability for every line
  • Federal + California state returns
Standalone quickstart

OpenClaw plugin

Tax filing as an agent tool. 16 tool definitions, SSE streaming, and a REST API — purpose-built for conversational AI agents.

  • Drop into any OpenClaw-compatible agent
  • TaxService API for Node.js
  • Full trace metadata in every response
Plugin integration guide

What's supported

Comprehensive coverage for common federal tax situations, with more forms being added.

Form 1040
Individual Income Tax
Schedule A
Itemized Deductions
Schedule B
Interest & Dividends
Schedule D
Capital Gains & Losses
Schedule E
Rental Income
Form 8949
Sales of Capital Assets
Form 8889
Health Savings Accounts
Form 6251
Alternative Minimum Tax
W-2
Wage Import
1099 Series
INT / DIV / B / R
Schedule C
Self-Employment Income
Schedule SE
Self-Employment Tax
Form 8962
Premium Tax Credit
Form 1116
Foreign Tax Credit
Form 8995
QBI Deduction (Sec. 199A)
Schedule K-1
Passthrough Income
Credits
Child Tax, Education, & more
CA 540
California State Return

How it works

Three steps to a completed return. No account required.

1

Upload documents

Import your W-2s, 1099s, and other tax documents. Data is extracted locally in your browser.

2

Review computed return

Walk through a guided interview. Every computed value is explainable — click to trace it back to source.

3

File or print

Download IRS-ready PDF forms for e-filing through IRS Free File or printing for mail submission.

Get started

Run OpenTax locally in under a minute. All you need is Node.js.

Terminal
$ git clone https://github.com/xavierliwei/opentax.git
$ cd opentax
$ npm install
$ npm run dev

# Open http://localhost:5173 in your browser