Open-source Desktop App
Tax software wants your SSN on someone else's server. OpenTax is a desktop app for self-employed Americans where the AI helps with the bookkeeping but your identity never touches the network.
The Product
Tax software wants your SSN on someone else's server. OpenTax is a desktop app for self-employed Americans where the AI helps with the bookkeeping but your identity never touches the network.
Under the Hood
OpenTax imports bank and card statement PDFs, PayPal CSVs, and Amazon order history, then uses Claude to categorize transactions, routing complex judgment calls to a stronger model and bulk work to a cheaper one. A seven-module tax engine computes self-employment tax, federal, state, and education credits, then fills the actual IRS PDFs. Personally identifying data lives in an encrypted local vault (AES-256-GCM, Argon2id) and is injected into the forms offline as the final step.
Deep Dive
## What we built A privacy-first tax preparer: statement import, AI-assisted categorization with human reconciliation, a deterministic tax engine, and real IRS PDF output. The AI sees transactions; it never sees your SSN. ## Tech Electron 33 with React 19 and TypeScript, SQLite with Drizzle, Anthropic API with vision for scanned statements, pdf-lib for form filling, AES-256-GCM vault keyed by Argon2id. ## Results 6 IRS form PDFs bundled and filled, a 7-module tax engine, 13 screens, and a hard architectural guarantee that identity data stays offline. ## What is next More state modules and a broader importer catalog, contributions welcome.
The Outcome
Fills 6 real IRS forms including the 1040 and Schedules C and SE
PII never leaves the machine: encrypted local vault injected offline
AI categorization with two-tier model routing for cost control
imports bank PDFs and PayPal CSVs and Amazon orders
13-screen guided flow from onboarding to export
open source under AGPL-3.0
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