OPEN-SOURCE TAX SOFTWARE // AUDITABLE ENGINE // LOCAL-FIRST

Build draft returns. Verify every step.

Use the open-source engine to assemble draft federal and state returns, inspect the calculation trail, and export reference PDFs for your own review. Do not rely on the software as a substitute for licensed tax advice, tax preparation, or independent accuracy review.

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OPEN SOURCE MOMENTUM

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github.com/utilityfueled/tax-engine
Federal + all 50 states2025 tax-year coverageReference PDFs, not e-file

Your Returns

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Why Viva La Tax

Auditable engine

Inspect how each draft result was calculated

Local-first storage

Returns stay in your browser by default in local mode

Experimental output

Review everything independently before filing or relying on it

Hosted plans are software tools

Sync, reminders, and AI helper budgets for tax year 2025