LedgerJack

Free, private, AI-powered — files to HMRC, never sells your data.

LedgerJack is a free, offline-first, end-to-end-encrypted bookkeeping app for UK self-employed people (sole traders, subcontractors, landlords). It keeps your records on your device, helps you stay MTD-ready, and files to HMRC — without ads, paywalls, or selling your data.

Status: pre-launch. Feature-complete against its roadmap and self-tested, but not yet independently audited or on HMRC's recognised-software list. Read "Before you rely on it" below. Figures the app prepares are provisional — discuss anything important with a qualified accountant.

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What it does

• Bookkeeping: double-entry ledger, receipts, mileage, CSV import, review queue.
• Making Tax Digital (Income Tax): connect to HMRC, quarterly updates, final declaration (sandbox-first).
• VAT (MTD): a 9-box return bridge — you confirm the figures, it submits.
• Tax estimate + tax pot: know roughly what to set aside, and when it's due.
• AI (your own key): scans receipts, one-line/voice entry, and explains your numbers in plain English — on your OpenRouter key, with the cost shown, and it never invents figures.
• Invoicing suite: invoices + quotes, PDF, client book, recurring invoices, multi-currency, overdue reminders, statements, share via email/WhatsApp/Telegram.
• Power bookkeeping: categorisation rules (with learning), recurring transactions, budgets, multiple trades/property.
• CIS: record subcontractor payments and deductions (labour-only).
• Statements: provisional P&L, balance sheet, cash flow, SA103, CSV for your accountant.
• Backup: end-to-end-encrypted backup to a file, your own cloud, or WebDAV.
• Security: on-device AES-GCM vault, recovery key, optional biometric unlock.

Tech stack

React 18 + TypeScript + Vite + Tailwind, Dexie.js (IndexedDB) for local storage, an optional Supabase Edge Function as a zero-knowledge relay for HMRC calls. Everything sensitive is encrypted client-side; there is no server that can read your data.

Getting started

npm install
npm run dev        # local dev server
npm run build      # production build (PWA)
npm run typecheck  # TypeScript checks
npm run lint       # lint

The HMRC relay lives in supabase/functions/hmrc-relay. Deploy it to your own Supabase project and set the allowed origins before using live MTD features. See docs/ for feature-by-feature notes.

Privacy & security model (short version)

• Your ledger lives in your browser's IndexedDB; sensitive fields and backups are encrypted with a key derived from your password and never leave the device.
• The HMRC relay is zero-knowledge: it forwards signed requests and cannot read your data.
• AI runs on your OpenRouter key; your figures pass to the model you choose, governed by your OpenRouter data settings. AI is opt-in and cost is shown.

Full details and threat model: SECURITY.md.

Before you rely on it (launch checklist)

• HMRC recognition: not yet on GOV.UK's recognised MTD-software list. Don't present it as recognised until it is.
• Verify external facts: HMRC MTD/VAT endpoint versions, OpenRouter model slugs/prices, CIS rates, and the 2026/27 tax-rate tables (all flagged in code).
• Device-test biometric unlock (WebAuthn PRF) on real iOS/Android/Windows.
• Smoke-test in a browser — automated checks here are static + logic tests.
• Independent security review before handling real users' tax data.

Contributing

See CONTRIBUTING.md. In short: keep it private-by-default and offline-first, add a self-test for any money/tax logic, and never introduce a server dependency for core features without discussion.

Licence

LedgerJack is licensed under the GNU Affero General Public License v3.0 (AGPL-3.0-or-later) — see LICENSE. In short: it's free to use and modify, but anyone who distributes it or runs a modified version as a network service must release their source under the same licence. This keeps LedgerJack free and open and stops it being turned into a closed, proprietary product.

The copyright holder retains all ownership and, as the rights holder, may also offer LedgerJack under separate commercial terms (dual licensing). The AGPL applies to everyone else; it does not restrict the owner.

Disclaimer

LedgerJack is bookkeeping software, not a substitute for professional advice. It produces provisional figures to help you keep good records and stay MTD-ready. Always check important numbers with a qualified accountant, and confirm your obligations with HMRC.