E-invoicing API for Germany and the EU

Check invoice XML before the next step in your billing workflow. Use structured preflight findings, generate XRechnung UBL for email sending, and process inbound invoices with EU/EEA-hosted primary service data.

Get started free Try the validation example

Everything the product needs. Nothing it does not.

A focused API surface with production controls, predictable resources, and the operational visibility to run email confidently.

01

UBL and CII XML preflight

Detect invoice format, check XML well-formedness and required fields, and receive structured errors and warnings. These built-in checks are not full XSD/Schematron validation.

02

Send e-invoices by email

Generate XRechnung UBL from structured invoice data and attach the XML to an email. Email delivery is separate from the recipient accepting or paying an invoice.

03

Receive and parse inbound invoices

Route incoming invoice messages into your application using configured inbound addresses and webhooks. Review supported parsing formats and attachment handling in the invoice docs.

04

EU/EEA-hosted primary service data

Primary invoice service data is hosted in the EU/EEA. Limited infrastructure metadata may be processed by providers under appropriate transfer safeguards.

05

Keep conformance checks explicit

A passing preflight result does not establish standards conformance, tax compliance, or buyer acceptance. Use the appropriate official validator and the recipient’s submission rules.

06

Works with your ERP

Call the REST endpoint from your billing system with a server-side API key. Handle valid: false even when the HTTP response is 200.

Start with one request.

The public API uses explicit resources and familiar JSON. Move from a first request to production without changing integration models.

Try the validation example

cURL: validate an XRechnung file ready

curl -X POST https://api.postscale.io/v1/invoices/validate \
  -H "Authorization: Bearer $POSTSCALE_API_KEY" \
  -H "Content-Type: application/xml" \
  --data-binary @invoice.xml

# Response
{
  "valid": true,
  "format": "xrechnung-ubl",
  "standard": "EN 16931",
  "errors": [],
  "warnings": []
}

FAQ

What is XRechnung and how does it relate to E-Rechnung?

E-Rechnung refers to electronic invoicing. XRechnung is a German specification based on EN 16931, with UBL and CII syntaxes. Check your buyer’s requirements separately from the API’s built-in preflight result.

Do you also support ZUGFeRD and Factur-X?

ZUGFeRD and Factur-X combine PDF and invoice XML. The validation endpoint detects PDFs but does not validate their embedded XML; use XML for preflight checks. The invoice-send endpoint generates UBL XML attachments, not interchangeable PDF formats.

Is the data processed in the EU?

Postscale is operated by DNScale OÜ (Estonia, EU). Primary invoice service data is hosted in the EU/EEA, with appropriate transfer safeguards for limited infrastructure metadata where required. We sign a standard GDPR DPA.

Can I test before committing?

Use the free browser validator or a test API key for XML preflight. Test keys do not send real email. Live invoice sending is separate and requires account approval and a verified sending domain; review the current setup and plan requirements.

Build the email workflow your product needs.

The free tier includes everything required to evaluate the API. No credit card required.

Create a free account