german-accounting

Machine-readable SKR03/SKR04 chart of accounts with MCC-to-account mapping for German SME accounting. MIT licensed — code and data.

The only open source dataset combining enriched SKR03/SKR04 metadata with ISO 18245 MCC codes mapped to specific German accounts. Use it from any language: download the JSON files directly or install the npm package for a typed TypeScript API.

npm install german-accounting

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Quick start

import { SKR03, suggestAccount } from "german-accounting";

// Look up an account
const konto = SKR03.get("4650");
// { konto: "4650", name: "Bewirtungskosten", klasse: 4, typ: "aufwand",
//   ust_relevant: true, steuerschluessel: [9], skr04: "6640", ... }

// Categorize a card transaction by MCC
const suggestion = suggestAccount("5812"); // restaurant
// {
//   mcc: "5812",
//   mcc_name: "Eating Places, Restaurants",
//   primary: { konto: "4650", confidence: "high", condition: null },
//   alternatives: [{ konto: "1800", condition: "If private meal" }],
//   needs_beleg: true,
//   ust_abzug: true
// }

// SaaS subscriptions (GitHub, Slack, Notion, Figma...)
suggestAccount("5817").primary.konto; // "4969" — Software-Nutzungsrechte

// Target SKR04 instead of SKR03
suggestAccount("5812", "SKR04").primary.konto; // "6640"

// Returns undefined for unknown MCCs — no throws
suggestAccount("9999"); // undefined

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API

SKR03 / SKR04

Pre-loaded chart-of-accounts singletons. Both are instances of Kontenrahmen.

SKR03.get("4650")           // → Konto | undefined
SKR03.search("Reisekosten") // → readonly Konto[]  (case-insensitive substring)
SKR03.klasse(4)             // → readonly Konto[]  (all Klasse 4 expense accounts)
SKR03.exists("4650")        // → boolean
SKR03.size                  // → number

suggestAccount(mcc, skr?)

suggestAccount(mcc: string, skr?: "SKR03" | "SKR04"): MCCSuggestion | undefined

MCC range entries (airlines 3000–3350, hotels 3351–3500, car rentals 3501–3999) are expanded at load time. Any code in those ranges resolves correctly.

When skr = "SKR04", the primary account is the skr04_primary value. name is null and alternatives is empty (no SKR04 name data in v0.1).

Types

interface Konto {
  konto: string;                                   // "4650"
  name: string;                                    // "Bewirtungskosten"
  klasse: number;                                  // 4
  typ: "aufwand" | "ertrag" | "aktiv" | "passiv";
  gruppe: string;
  untergruppe?: string;
  ust_relevant: boolean;
  steuerschluessel: readonly number[];
  skr04?: string | null;   // cross-ref to SKR04 account (SKR03 only)
  skr03?: string | null;   // back-ref to SKR03 account (SKR04 only)
  notes?: string | null;
}

interface MCCSuggestion {
  mcc: string;
  mcc_name: string;
  category: string;
  primary: AccountSuggestion;
  alternatives: readonly AccountSuggestion[];
  needs_beleg: boolean;
  ust_abzug: boolean;
  notes: string | null;
}

interface AccountSuggestion {
  konto: string;
  name: string | null;
  confidence: "high" | "medium" | "low";
  condition: string | null;
}

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Data files

The JSON files are the primary product. Download them from GitHub Releases to use without Node.

File	Contents
src/data/skr03.json	289 SKR03 accounts with enriched metadata and SKR04 cross-references
src/data/skr04.json	254 SKR04 accounts derived from SKR03 cross-references
src/data/mcc_skr_mapping.json	230 MCC mappings with confidence levels and alternatives

JSON Schemas are in schemas/ and validated by CI on every push.

Data schema — skr03.json

{
  "meta": { "version": "2026.1", "last_updated": "2026-04-03", ... },
  "klassen": [{ "klasse": 0, "name": "Anlage- und Kapitalkonten" }, ...],
  "konten": [
    {
      "konto": "4650",
      "name": "Bewirtungskosten",
      "klasse": 4,
      "typ": "aufwand",
      "gruppe": "Betriebliche Aufwendungen",
      "ust_relevant": true,
      "steuerschluessel": [9, 8],
      "skr04": "6640"
    }
  ]
}

Data schema — mcc_skr_mapping.json

{
  "meta": { "version": "2026.1", ... },
  "mappings": [
    {
      "mcc": "5812",
      "mcc_name": "Eating Places, Restaurants",
      "category": "Food & Beverage",
      "skr03": { "primary": "4650", "confidence": "high" },
      "skr04_primary": "6640",
      "alternatives": [
        { "konto": "1800", "condition": "If private meal" }
      ],
      "needs_beleg": true,
      "ust_abzug": true
    }
  ]
}

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Contributing

Add or fix an MCC mapping

1. Edit mcc_skr_mapping.json. Required fields: mcc, mcc_name, category, skr03.primary, skr03.confidence, skr04_primary, needs_beleg, ust_abzug.
2. Run npm test — CI gate verifies that all referenced accounts exist in skr03.json.
3. Open a PR using the MCC mapping template. Include the account number, confidence level, your rationale, and your source (DATEV docs, Steuerberater guidance, SKR documentation).

Confidence guidelines:

• high — the MCC strongly implies a specific account with no real ambiguity (e.g., fuel stations → Kfz-Betriebskosten)
• medium — likely correct but depends on context (e.g., office supply store → could be Bürobedarf or a larger asset)
• low — genuinely ambiguous; the mapping is a reasonable default but alternatives are common

Add or fix SKR03 accounts

Edit skr03.json directly. All fields from the schema are required. Run npm test to verify referential integrity before opening a PR.

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Versioning

Data is versioned independently from the package using a year-based scheme (2026.1, 2026.2, ...). The package version tracks the API.

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License

MIT — code and data.