ELSTER — the federal tax platform

ELSTER (Elektronische Steuererklärung) is the German electronic tax-filing platform, jointly operated by the Bundeszentralamt für Steuern (BZSt) and the 16 Länder finance ministries. Central brick of digital German taxation, it remains independent of the 2025-2028 E-Rechnung reform — but intersects on VAT and the intra-EU recapitulative statement.

Bund / BZSt / Länder governance

ELSTER rests on the constitutional separation of tax powers in Germany: the Bund legislates, but actual administration (collection, audit) belongs to the Länder. This duality explains the complexity:

• BZSt — Bundeszentralamt für Steuern. Federal tax office in Bonn. Competence over federal returns: Körperschaftsteuer (inter-Länder corporate tax), withholding tax, Zusammenfassende Meldung (intra-EU), MOSS / OSS / IOSS (EU e-commerce VAT).
• Finanzämter (Länder). Regional tax offices, around 600 across Germany. Competence over local returns: Einkommensteuer (income tax), Umsatzsteuer (VAT), Lohnsteuer (payroll), Gewerbesteuer (trade tax).
• Bayerisches Landesamt für Steuern (BayLfSt). Historical ELSTER technical host on behalf of all Länder + Bund, based in Munich. Maintains production infrastructure.
• KONSENS — Koordinierte neue Software-Entwicklung der Steuerverwaltung. Federal tax IT modernisation programme launched in 2007, governs ELSTER evolutions with a Bund/Länder steering committee.

Supported tax returns

ELSTER covers the full range of German tax returns, ~50 main forms. Most relevant for businesses and electronic invoicing:

USt-Voranmeldung — VAT pre-filing

The USt-Voranmeldung (USt-VA) is the most frequent return, pivot of the German VAT framework. Mandatory by electronic means since 2005 (§18 (1) UStG), filing is via ELSTER no later than the 10th day of the following month.

• Frequency. Monthly if collected VAT > €7,500 / year, quarterly between €1,000 and €7,500, exemption if < €1,000. Kleinunternehmer §19 UStG are exempt.
• Main lines (Kennziffern). Kz 81 (turnover at standard rate 19%), Kz 86 (turnover at reduced rate 7%), Kz 35 (exempted intra-EU shipments), Kz 66 (deductible input VAT — Vorsteuer), Kz 39 (reverse-charge §13b UStG).
• Deadlines and penalties. Late filing: interest 0.5% per month (§240 AO). Beyond 14 days, surcharge up to 10% of the amount (Verspätungszuschlag).
• Compatible with Dauerfristverlängerung. On request, permanent 1-month extension subject to upfront deposit of 1/11 of annual VAT payment (Sondervorauszahlung).

<?xml version="1.0" encoding="ISO-8859-15"?>
<Anmeldungssteuern art="UStVA" version="2026">
  <DatenLieferant>
    <Name>Beispiel GmbH</Name>
    <Strasse>Hauptstrasse 12</Strasse>
    <PLZ>10115</PLZ>
    <Ort>Berlin</Ort>
    <Telefon>+49 30 12345678</Telefon>
  </DatenLieferant>
  <Erstellungsdatum>20260519</Erstellungsdatum>
  <Steuerfall>
    <Unternehmer>
      <Bezeichnung>Beispiel GmbH</Bezeichnung>
      <Strasse>Hauptstrasse 12</Strasse>
      <PLZ>10115</PLZ>
      <Ort>Berlin</Ort>
    </Unternehmer>
    <Umsatzsteuervoranmeldung>
      <Jahr>2026</Jahr>
      <Zeitraum>05</Zeitraum>
      <Steuernummer>1011281508156</Steuernummer>
      <Kz81>153000</Kz81>  <!-- Turnover 19% -->
      <Kz86>15000</Kz86>   <!-- Turnover  7% -->
      <Kz66>32070</Kz66>   <!-- Input VAT (Vorsteuer) -->
    </Umsatzsteuervoranmeldung>
  </Steuerfall>
</Anmeldungssteuern>

Zusammenfassende Meldung intra-EU

The Zusammenfassende Meldung (ZM — recapitulative statement) collects intra-EU B2B supplies and services. German equivalent of the European VIES return (VAT Information Exchange System) — sent directly to BZSt which then syncs with the EU.

• Legal basis: §18a UStG, transposition of Directive 2006/112/EC art. 262-271.
• Frequency: monthly for intra-EU goods shipments if > €50,000 / quarter; quarterly otherwise. Intra-EU B2B services remain quarterly.
• Format: normalised XML via ERiC SDK, ELSTER transmission to BZSt Saarlouis.
• Content: per EU counterpart — VAT number of the customer, net total amount, distinction goods / services / triangular.
• No invoice-level granularity: unlike Polish SAF-T or Spanish SII, the ZM is aggregated by partner and period — not invoice-by-invoice reporting.

ERiC — technical integration API

ERiC (ELSTER Rich Client) is the proprietary SDK distributed by the Bayerisches Landesamt für Steuern to accounting software vendors. The only automated integration route into ELSTER — the web platform is reserved for manual entry.

┌──────────────┐                                  ┌───────────────────┐
│ ERP / Acct.  │   1. ERiC.bearbeiteVorgang()    │  ERiC SDK (DLL)   │
│  (Datev,     │ ───────────────────────────────> │   - Schema valid. │
│   Lexware,   │                                  │   - Signing       │
│   SAP)       │ <─── 2. Signed token ─────────── │   - Compression   │
└──────────────┘                                  └───────────────────┘
                                                          │
                                                          ▼
                                                  ┌───────────────────┐
                                                  │  ELSTER Clearing  │
                                                  │  (BZSt + Länder   │
                                                  │  Telematics)      │
                                                  └───────────────────┘
                                                          │
                                       ┌──────────────────┴──────────────────┐
                                       ▼                                     ▼
                              ┌──────────────────┐                  ┌──────────────────┐
                              │ Bundeszentralamt │                  │ Finanzamt        │
                              │ für Steuern (ZM, │                  │ Land level       │
                              │ KSt, intra-EU)   │                  │ (USt-VA, ESt)    │
                              └──────────────────┘                  └──────────────────┘

• Distribution. Under contract with BayLfSt, royalty-free for vendors. Available Windows 64-bit, Linux x86_64, macOS Intel/ARM. Annual update to track form evolutions.
• Main functions: XSD document validation, cryptographic sealing with ELSTER-Zertifikat, compression, HTTPS transmission, acknowledgement of receipt (Telenummer).
• Integration language: C/C++ DLL natively, third-party wrappers for Java, .NET, Python.
• Competitors: Datev (90% of the German accounting-firm market), Lexware Buchhalter, Sage 50, Stotax — all major vendors integrate ERiC internally.

Interaction with the E-Rechnung reform

Frequent question: will ELSTER receive B2B invoices after 1 January 2025? No, not directly. The German E-Rechnung reform remains decentralised — no central platform like SdI or KSeF. But interaction with ELSTER exists and will strengthen:

• Mitteilungspflicht (reporting obligation) — gestation 2026-2028. BMF launched in May 2025 a consultation on a future B2B invoicing data reporting mechanism to ELSTER, complementing USt-VA / ZM returns. Envisaged model: streaming extraction on the ERP vendor side, ELSTER transmission triggered at the monthly return.
• Enriched ZM (intra-EU). For intra-EU transactions, the BMF letter of 15 October 2024 confirms the ZM will be enriched with detailed fields from July 2028 onwards (coupling with EU ViDA — VAT in the Digital Age).
• No B2B invoice transmission API to ELSTER. Different from Polish KSeF or Italian SdI. B2B invoices remain exchanged P2P between issuer and recipient; ELSTER sees only the declared aggregates.

Cross-links

• Germany hub — full e-invoicing mandate
• Wachstumschancengesetz — legal foundation
• XRechnung — German CIUS
• German VAT regimes
• ELSTER — official portal
• Bundeszentralamt für Steuern (BZSt)
• ERiC SDK — vendor distribution
• §18 UStG — Voranmeldung obligation
• §18a UStG — Zusammenfassende Meldung