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Fiscal Architect

A private tax and revenue simulator for French micro-entrepreneurs.

Plan revenue, social contributions, income tax, VAT thresholds and cash collection from a fully client-side PWA.

Open the app

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What It Does

Fiscal Architect helps French freelancers and small independent businesses simulate the practical side of a micro-entreprise:

• revenue input by worked days, fixed-price work, monthly totals, or mixed mode;
• multi-activity profiles across sales, BIC services, liberal SSI and liberal CIPAV;
• URSSAF, CFP, chamber tax, ACRE, income tax and versement liberatoire simulation;
• micro-enterprise and VAT franchise threshold tracking;
• cashflow projection from invoice dates to expected payment dates;
• multi-year navigation and local backup export/import.

The application has no backend, no account system and no tracking. User data stays in the browser through localStorage.

Developer Overview

Area	Choice
Framework	React 19 + TanStack Start
Routing	TanStack Router file routes
Build	Vite 8
Styling	Tailwind CSS 4 with theme tokens
Charts	Recharts
Animation	Motion
Icons	Lucide React
Tests	Vitest
Persistence	Versioned localStorage hooks

Project Structure

src/
  components/       Shared UI and feature components
  context/          App providers for profile, fiscal year, theme and notifications
  hooks/            Browser state, storage and interaction hooks
  lib/              Fiscal engine, calendar logic, cashflow, import/export and tests
  pages/            Main application screens
  routes/           TanStack Router route entries
  styles/           Tailwind theme and global styles

Local Development

corepack enable
pnpm install
pnpm dev

The dev server runs on http://localhost:4000.

Command	Description
pnpm dev	Start the local dev server
pnpm build	Build the production app
pnpm lint	Run TypeScript checks
pnpm test	Run the Vitest suite
pnpm clean	Remove generated build folders

Node 22 is required. See .nvmrc.

Fiscal Scope

The tax engine source of truth lives in src/lib/fiscal.ts.

Activity	URSSAF	Allowance	Micro threshold	VL
Sales / accommodation	12.3%	71%	EUR 203,100	1.0%
BIC services / craft	21.2%	50%	EUR 83,600	1.7%
Liberal SSI	25.6%	34%	EUR 83,600	2.2%
Liberal CIPAV	23.2%	34%	EUR 83,600	2.2%

Other modeled rules include VAT franchise thresholds, ACRE reduction windows, RFR-based versement liberatoire eligibility, liberal daily benefits and the dedicated bank-account alert.

Quality Notes

• Calculation-heavy logic is isolated in src/lib and covered by Vitest.
• Persistent objects carry schemaVersion fields and can be migrated through useVersionedStorage.
• The app is designed to remain usable offline after the first load.
• Import/export uses an application backup format rather than CSV, because it is intended for restore workflows.

Disclaimer

Fiscal Architect provides estimates for informational purposes only. It does not replace professional tax advice. Always cross-check important figures with URSSAF, Service-Public.fr, or an accountant.

License

MIT © Maxime Morellon