invoiceapi.io

German e-invoicing mandate 2027

Beautiful invoices. Valid e-invoices. One API.

invoiceapi.io turns your designed template into validated ZUGFeRD and XRechnung documents: via REST API, delivered and archived. Built for developers, agencies and SaaS teams that must ship before 2027.

Get early access

Beta: September 2026 · Launch: October 2026 · from €49 / month (planned)

POST /v1/templates/…/invoices
curl -X POST https://api.invoiceapi.io/v1/templates/tpl_9x2/invoices \
  -H "Authorization: Bearer sk_live_…" \
  -d '{
    "seller":   { "name": "Musterbau GmbH", "vat_id": "DE123456789" },
    "buyer":    { "name": "Beispiel AG" },
    "items":    [{ "name": "Beratung", "qty": 8, "unit_price": "120.00", "vat": "19" }]
  }'

→ 201 { "zugferd_pdf": "https://…/re-2026-0042.pdf",
        "xrechnung_xml": "https://…/re-2026-0042.xml",
        "validation": "passed (KoSIT 3.x)" }

Why now

From January 1, 2027, a PDF is no longer enough.

Germany is mandating e-invoicing for domestic B2B. A regular PDF will then only count as an "other invoice" (sonstige Rechnung), legally insufficient for domestic B2B transactions.

  1. Since Jan 1, 2025

    All businesses must be able to receive e-invoices.

  2. From Jan 1, 2027

    Issuing becomes mandatory for businesses above €800,000 in prior-year revenue.

  3. From Jan 1, 2028

    Issuing becomes mandatory for all businesses.

The required format is structured XML per EN 16931: XRechnung or ZUGFeRD. Your invoice PDF from Puppeteer, wkhtmltopdf or jsPDF does not qualify.

Three steps

01

Design

Pick a professional, DIN 5008-compliant layout and adjust logo, colors, columns and labels in the browser. No pixel-pushing, no page-break bugs.

02

Send

POST your JSON to your template’s API. One schema, cleanly documented, with error messages written for humans.

03

Done

You get back a valid ZUGFeRD hybrid PDF or an XRechnung: delivered by email on request and kept in an immutability-oriented archive.

Features

KoSIT-validated

Every invoice passes the official Schematron validation before it leaves your system.

XML ↔ PDF guaranteed consistent

The embedded XML is the legally authoritative document. With us, data and design always match.

GoBD-oriented archive

Stored immutably, with audit trail and export. Hosted exclusively in Germany.

Multi-tenant

One agency, many clients: cleanly separated profiles per tenant.

Error messages for humans

"Seller VAT ID missing (BT-31)" instead of Schematron cryptic output. In German and English.

Beyond the mandate

B2C, low-value invoices, cross-border invoices, quotes and delivery notes as classic PDFs, from the same template.

Who it’s for

Agencies & freelancers

From 2027 every client will ask you the same question. Answer with one API instead of twelve one-off builds.

SaaS products

Your users expect compliant invoices out of your product. White-label, via API.

Internal dev teams

Your homegrown invoice PDF has an expiry date. Migrate in a sprint, not a quarter.

FAQ

What is an e-invoice?

A structured XML dataset per EN 16931 that software can process automatically. A regular PDF is not an e-invoice: from 2027/2028 it only counts as an "other invoice" for domestic German B2B.

Is ZUGFeRD by email really sufficient?

Yes. Germany mandates the format, not the transmission channel. A valid ZUGFeRD PDF sent by email fulfils the mandate; a Peppol network is not required for domestic B2B invoices.

What does it cost?

Planned: from €49 / month including the archive. Beta participants get founder terms.

I also need XRechnung for public authorities.

That is exactly what the API is built for: the same template, output either as a ZUGFeRD hybrid PDF or as XRechnung XML.

Is this tax advice?

No. invoiceapi.io is a technical tool for formats, validation and archiving. For tax questions, talk to your tax advisor.

Get early access

We launch in October 2026, in time for the first mandate stage. Sign up for beta access and founder pricing.