@autonomynexus/accounting

Comprehensive French accounting engine, fully PCG-compliant (Plan Comptable Général — Règlement ANC N° 2014-03). Handles double-entry bookkeeping, VAT declarations (CA3/CA12), URSSAF contributions, financial statements, liasse fiscale, IS computation, BNC 2035, amortization, FEC generation — with zero infrastructure dependencies.

Why this exists

French accounting for freelancers (EI, micro-entreprise) and small companies (EURL, SASU, SAS) involves a maze of tax regimes, URSSAF rates, VAT thresholds, and filing obligations. This package encodes all of that as pure TypeScript — no database, no framework, no runtime dependencies beyond Effect and monetary.

What's included

Core Accounting Engine

• Full PCG Chart of Accounts — 380+ standard accounts, all classes 1-8, with hierarchy, metadata, and lookup functions
• Double-entry bookkeeping — journal types (HA/VE/BQ/OD/AN), écriture validation, debit=credit enforcement
• Trial balance (balance des comptes) — computed from journal entries
• General ledger (grand livre) — with running balances per account
• Subsidiary ledger (balance auxiliaire) — for clients (411) and suppliers (401)
• Lettrage (account matching) — client payments to invoices, supplier payments
• Bank reconciliation types (rapprochement bancaire)
• Year-end closing (clôture d'exercice) — generates closing entries, computes résultat
• Opening entries (à-nouveaux) — generates from prior year closing balance
• Exercice management — fiscal year lifecycle, multi-exercise support

Financial Statements

• SIG (Soldes Intermédiaires de Gestion) — marge commerciale, VA, EBE, résultat d'exploitation, résultat courant, résultat net
• Balance sheet (bilan) — from trial balance
• Income statement (compte de résultat) — from P&L accounts

Tax Declarations

• CA3 — monthly/quarterly VAT declaration with all 32 official lines
• CA12 — annual simplified VAT declaration
• VAT annexes — 3310-A (taxes assimilées), 3310-TER (secteurs distincts), 3310-TIC (accises)
• 2035 BNC — declaration contrôlée for profession libérale (2035-A recettes/dépenses, 2035-B immobilisations)

Liasse Fiscale (IS)

• 2050 — Bilan Actif (computed from trial balance)
• 2051 — Bilan Passif
• 2052 — Compte de Résultat (charges)
• 2053 — Compte de Résultat (produits)
• 2054-2056 — Immobilisations, amortissements, provisions (models)
• 2058-A — Détermination du résultat fiscal (passage comptable → fiscal)

IS Computation

• 2572-SD — relevé de solde IS
• Taux réduit 15% (≤ €42,500 si CA < €10M) + taux normal 25%
• Contribution sociale (3.3% si IS > €763K)
• Acomptes trimestriels
• Report en avant des déficits (1M€ + 50% au-delà)

FEC Generation

• Full Fichier des Écritures Comptables (Article A.47 A-1 LPF)
• Tab-separated export with French number formatting
• Validation (mandatory fields, debit=credit, sequential numbering)
• Filename convention: {SIREN}FEC{YYYYMMDD}.txt

Amortization Engine

• Linear (amortissement linéaire)
• Declining balance (amortissement dégressif) with PCG coefficients
• Prorata temporis for partial-year acquisitions
• Asset disposal (cession) with plus/moins-value computation

URSSAF

• Contribution computation with ACRE support
• Rate tables for all activity types
• Versement libératoire

Threshold Monitoring

• Micro-entreprise revenue thresholds
• Regime transition warnings

Architecture

Ports & Adapters. Services define what data they need through ports (interfaces). You provide adapters — from a database, from static data, from an API.

┌─────────────────────────────────┐
│   @autonomynexus/accounting     │
│                                 │
│  Pure Computations (no deps)    │
│  Effect Services ──→ Ports      │
│  PCG, Rates, Thresholds         │
└─────────────┬───────────────────┘
              │ you provide
┌─────────────▼───────────────────┐
│  Your Adapters                  │
│  (Drizzle, Prisma, static, ..) │
└─────────────────────────────────┘

Install

bun add @autonomynexus/accounting
bun add monetary  # peer dependency

Quick Start

Pure computations (no Effect needed)

import {
  // PCG chart of accounts
  PCG_ACCOUNTS_FULL, getAccountByCode, getAccountsByClass,
  // Double-entry engine
  validateEcriture, computeTrialBalance, computeGrandLivre,
  computeClotureExercice, computeANouveau,
  // Financial statements
  computeSIG,
  // IS computation
  computeIS, computeAcomptes, applyDeficitReportEnAvant,
  // Amortization
  computeAmortissementLineaire, computeAmortissementDegressif,
  // FEC
  generateFecRecords, exportFecToString, validateFecRecords,
  // VAT
  calculateHTFromTTC, FRENCH_VAT_RATES,
  // Liasse fiscale
  computeForm2050, computeForm2051, computeForm2052, computeForm2053,
} from "@autonomynexus/accounting";

IS computation example

import { computeIS } from "@autonomynexus/accounting";
import { EUR, monetary } from "monetary";

const m = (euros: number) => monetary({ amount: euros * 100, currency: EUR });

const result = computeIS({
  resultatFiscal: m(50000),
  chiffreAffairesHT: m(500000),
  acomptesVerses: m(0),
  creditsImpot: m(0),
  siren: "123456789",
  denomination: "Ma SAS",
  exerciceDateDebut: new Date(2024, 0, 1),
  exerciceDateFin: new Date(2024, 11, 31),
  dureeExerciceMois: 12,
});
// result.isBrut → IS dû
// result.eligibleTauxReduit → true (CA < 10M)

Tech Stack

• TypeScript, Effect, monetary
• Bun for runtime/testing (vitest)
• 69 tests covering all computation modules

Legal References

• PCG — Plan Comptable Général (Règlement ANC N° 2014-03)
• CGI Art. 287 — VAT declaration obligations
• CGI Art. 302 septies A — Régime simplifié (CA12)
• LPF Art. A.47 A-1 — FEC specification
• CGI Art. 219 — IS rates and conditions
• CGI Art. 209 — Deficit carry-forward rules

License

Private — Autonomy Nexus