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Tax and revenue simulator for every French micro-entrepreneur (auto-entrepreneur). Day-rate freelancers, fixed-price craftspeople, e-commerce sellers, ride-share drivers, short-term rental hosts, multi-activity profiles — track your revenue, split your contributions per activity, watch your thresholds, all in your browser with no backend and no tracking.
Tip
🚀 Open the app → install in one tap → use it offline fiscal-architect.vercel.app
Works in any modern browser. Install it as a real app on macOS · iOS · Android · Windows · Linux — no app store, no account, no server. Your data lives on your device only.
About the scope: this tool is built around the French tax system (micro-entreprise, URSSAF, BNC). The codebase is in English; the user-facing UI is in French.
Online tax calculators are either ad-ridden, send your numbers to third-party servers, or rely on outdated constants — and most only cover one type of micro-entreprise. Fiscal Architect is the opposite:
- 100% client-side — your data never leaves your browser (
localStorage). - All micro-entreprise activities — sales (BIC), commercial services / artisans, unregulated liberal (SSI), regulated liberal (CIPAV), with multi-activity ventilation per branch.
- Multiple input modes — daily calendar (rate × days), fixed-price quotes, aggregated monthly revenue, or mixed.
- 2026 constants up to date — URSSAF, allowances, micro and VAT thresholds, ACRE 50/25%, RFR for the versement libératoire.
- Open source, MIT — auditable, modifiable, deployable on your own infrastructure.
- Installable PWA — one-tap install on any device, works fully offline once loaded.
On first launch, pick your profile — input mode, activity and tax options are pre-filled for you. Everything stays adjustable later.
| Profile | Input mode | Default activity |
|---|---|---|
| Freelancer / consultant | Days worked × daily rate | Unregulated liberal (SSI) |
| Craftsperson / fixed-price provider | Dated one-off quotes | Commercial services / artisan |
| E-commerce / marketplace | Aggregated monthly revenue | Sales / accommodation (BIC) |
| Ride-share / delivery driver | Aggregated monthly revenue | Commercial services |
| Short-term rental host | Aggregated monthly revenue | Sales / accommodation |
| Free configuration | Mixed (up to 4 cumulative activities) | Your call |
Fiscal Architect is a Progressive Web App: just open the link, and your browser will offer to install it as a standalone app. No app store, no signup, no download manager — and once installed, it runs offline like a native app.
| Platform | How to install |
|---|---|
| macOS (Chrome, Edge, Brave) | Address bar → install icon, or menu → Install Fiscal Architect… |
| macOS (Safari 17+) | Share button → Add to Dock |
| iOS / iPadOS (Safari) | Share button → Add to Home Screen |
| Android (Chrome, Edge, Samsung) | Install banner, or menu → Install app / Add to Home Screen |
| Windows (Chrome, Edge) | Address bar → install icon, or menu → Apps → Install this site as an app |
| Linux (Chromium-based) | Address bar → install icon |
After the first visit, the app is also fully usable offline — your calendar, profile and simulations all live in localStorage on your device.
- 4 input modes — daily calendar, fixed-price quotes, aggregated monthly revenue, or mixed (free combination).
- Multi-activity — up to 4 cumulative activities with correct ventilation of URSSAF, CFP, chamber tax and income tax per branch, plus mixed thresholds.
- Multi-year —
‹ 2026 ›stepper for navigation, explicit transition popup when entering a new year (carry over the previous year's settings or start from default values), automatic patch of legal parameters (URSSAF, micro threshold). - Dark mode — light / dark / system theme with unified tokens (
@theme), respectsprefers-color-scheme, persisted per device. - Persona onboarding — first-launch modal offers 5 preset profiles that pre-fill the entire configuration.
- Dismissable notification center — header bell, count badge, hide compte pro / micro threshold alerts without losing them.
- Quick edit — click directly on displayed values (fixed expenses, identity…) to edit them without opening the settings drawer.
- Interactive calendar — full days, half-days, French public holidays, drag to fill a range, prefill business days.
- Triple threshold gauge — realised / projected / target for both the micro threshold and the VAT franchise en base threshold, with projected breach date.
- Complete tax charges — URSSAF, income tax (progressive bracket or flat-rate option), CFP, CCI/CMA chamber tax, optional daily benefits (liberals), ACRE 50%/25% with automatic 12-month window.
- VL eligibility check — enter your N-2 RFR and tax shares, the toggle is automatically disabled if the cap is exceeded.
- Mandatory pro account alert — banner and notification once cumulative revenue passes €10,000 (article L.123-24 of the French Commercial Code).
- Real-time simulation — sliders for daily rate / URSSAF / VL; everything recomputes live.
- Recurring fixed expenses — managed individually, factored into the monthly net.
| Domain | Choice |
|---|---|
| Framework | React 19 + TanStack Start + TanStack Router |
| Build | Vite 8 |
| Styles | Tailwind CSS 4 (@theme tokens) |
| Charts | Recharts |
| Animation | Motion |
| Icons | Lucide React |
| Tests | Vitest |
| Persistence | localStorage (via the useLocalStorage hook) |
git clone https://github.com/max-mxm/fiscal-architect.git
cd fiscal-architect
pnpm install
pnpm dev # http://localhost:4000| Command | Description |
|---|---|
pnpm dev |
Dev server (port 4000) |
pnpm build |
Production build |
pnpm lint |
TypeScript check (tsc --noEmit) |
pnpm test |
Vitest suite |
pnpm clean |
Remove dist/, .output/, .vinxi/ |
Node 22 required (see
.nvmrc). The package manager is pnpm (version pinned viapackageManagerinpackage.json); enable it withcorepack enable.
Source of truth in code: src/lib/fiscal.ts (ACTIVITY_PARAMS).
| Activity | URSSAF | Income-tax allowance | Micro threshold | VL | CFP | Chamber tax |
|---|---|---|---|---|---|---|
| Sales / accommodation (BIC) | 12.3% | 71% | €203,100 | 1.0% | 0.1% | 0.015% |
| Commercial services / artisan | 21.2% | 50% | €83,600 | 1.7% | 0.3% | 0.044% |
| Unregulated liberal (SSI) | 26.1% | 34% | €83,600 | 2.2% | 0.2% | 0 |
| Regulated liberal (CIPAV) | 23.2% | 34% | €83,600 | 2.2% | 0.2% | 0 |
| Cross-cutting concept | 2026 value |
|---|---|
| VAT franchise en base threshold — services / BNC | €36,800 (basic) · €39,100 (boosted) |
| VAT franchise en base threshold — sales | €91,900 (basic) · €101,000 (boosted) |
| 2026 income-tax brackets | 0 / 11 / 30 / 41 / 45% |
| ACRE (before 2024-05-01) | 50% URSSAF reduction for 12 months |
| ACRE (from 2024-05-01) | 25% URSSAF reduction for 12 months |
| RFR N-2 cap for VL eligibility | ≈ €27,478 per fiscal share |
| Mandatory dedicated bank account | from €10,000 revenue / 2 consecutive years |
| Liberal daily-benefits rate (option) | 0.85% of liberal revenue |
- Service threshold raised: €77,700 → €83,600 (applies to fiscal years 2026, 2027, 2028).
- +1 percentage point on social contributions for BNC libéral non réglementé starting 2026-01-01.
- ACRE: 25% rate since 2024-05-01 (50% before).
- Versement libératoire: eligibility now subject to the household's N-2 RFR (≈ €27,478 × fiscal shares).
- Pro bank account: L.123-24 obligation kicks in from €10,000 of revenue across 2 consecutive years.
For each activity a (with its CA_a):
URSSAF_a = CA_a × URSSAF_rate_a
CFP_a = CA_a × CFP_rate_a
Chamber_a = CA_a × chamber_rate_a (sales + BIC services only)
Taxable income_a = CA_a × (1 − allowance_a)
ACRE = Σ URSSAF_gross × (50% or 25%) for 12 months post-creation
Liberal IJ = (CA_liberalSsi + CA_liberalCipav) × 0.85% (option)
Total CA = Σ CA_a
URSSAF_net = Σ URSSAF_a − ACRE
Social charges = URSSAF_net + Σ CFP_a + Σ Chamber_a + IJ
Income tax (bracket)= progressive bracket applied to Σ Taxable income_a
Income tax (VL) = Σ CA_a × VL_rate_a
Net after income tax= Total CA − Social charges − Fixed expenses − Income tax
For a single-activity day-rate freelancer, CA_a = daily rate × days worked. For a fixed-price craftsperson, CA_a = Σ quote amounts. For a ride-share driver or e-commerce seller, CA_a = monthly aggregated amount.
- localStorage persistence for profile and calendar
- Centralized tax engine (
src/lib/fiscal.ts) with 227 Vitest tests - Interactive 12-month billing calendar
- Installable PWA (manifest + service worker)
- Pluggable input modes (days / fixed-price / monthly aggregated / mixed)
- Multi-activity with URSSAF / CFP / chamber tax / income tax ventilation per branch
- VAT franchise tracking + projected breach alert
- Dismissable notification center (pro account, micro threshold)
- Persona onboarding (5 preset profile types)
- Quick edit via popup (fixed expenses, identity)
- VL eligibility via N-2 RFR
- Optional liberal daily benefits
- Light / dark mode with unified tokens and
prefers-color-schemesupport - Multi-year — navigation stepper and transition popup (carry over from N-1 or default values)
Warning
Fiscal Architect provides estimates for informational purposes only. The application does not replace professional tax advice. Always cross-check your figures with URSSAF, Service-Public.fr, or your accountant. Tax constants evolve — if you spot an inconsistency, open an issue.
Contributions are welcome! Tax-constant corrections and additional tests are particularly appreciated. See CONTRIBUTING.md.
MIT © Maxime Morellon
- TanStack for Start & Router
- Recharts for the charts
- Lucide for the icons
- Tailwind CSS for the design system
- URSSAF auto-entrepreneur and Service-Public.fr — the canonical sources for French tax data