Summand 0.1.0 released

Summand 0.1.0 is out. It validates e-invoices against the official EN 16931 and XRechnung rules, in pure TypeScript. @sweberdev/summand is on npm under the MIT licence.

Why

Since 1 January 2025 every business in Germany must be able to receive e-invoices, and from 2027 most have to send them. An e-invoice is XML: XRechnung in UBL or CII syntax, or a ZUGFeRD / Factur-X PDF with the XML embedded. Whether such an invoice is correct is decided by a few hundred business rules, published as Schematron by CEN and KoSIT. Running them has so far meant the KoSIT validator: Java, Saxon and a server next to your application.

Summand runs the same rules where your code already runs: in a Node backend, a serverless or edge function, the browser before an upload, or CI.

What is in 0.1.0

• Its own XPath 2.0 and Schematron engine in TypeScript, with exact decimal arithmetic so that sums of amounts are compared without rounding errors.
• The official rule sets: CEN EN 16931 1.3.16 for UBL and CII, and KoSIT XRechnung 2.6.0 for XRechnung 3.0, including the severity changes KoSIT applies for the standard, extension and CVD profiles.
• All 1'142 CEN rule tests and every invoice of the KoSIT test suite pass.
• UBL Invoice, UBL Credit Note and CII are detected automatically, as are the profiles XRechnung, Peppol BIS, EN 16931 and Factur-X MINIMUM, BASIC WL, BASIC and EXTENDED.
• ZUGFeRD and Factur-X PDFs: Summand reads the embedded XML and compares the profile in the PDF metadata with the one in the XML.
• A Leitweg-ID check with the ISO 7064 check digits, because a typo there gets an invoice to a public buyer rejected.
• Every finding with rule ID, message, XPath and line, and a summary of the invoice with number, parties and totals.
• The summand CLI to validate files, extract the XML from a PDF and check Leitweg-IDs.

Summand does not check the XML schemas (XSD) yet, so it does not replace the KoSIT validator in every case. It checks invoices technically; it is not tax advice.

Install

pnpm add @sweberdev/summand

import { validateInvoice } from "@sweberdev/summand"

const result = validateInvoice(bytes) // XML string, XML bytes or a ZUGFeRD PDF

if (!result.valid) {
  for (const e of result.errors) console.log(e.id, e.message, e.line)
}

Or from the command line:

npx @sweberdev/summand validate invoice.pdf

Drop your own invoice into the live demo: it runs the real package in your browser, and nothing is uploaded. The full reference is at packages.sweber.dev/summand/docs.

Summand Pro

Summand Pro is for teams that process incoming invoices. summand-read turns any invoice, UBL or CII, XML or PDF, into one typed object with all EN 16931 business terms. summand-view renders it as readable, printable HTML in German or English with the validation report. summand-inbox validates whole folders, writes JSON, CSV, JUnit and HTML reports, finds duplicates across runs and keeps an audit log with the SHA-256 of every file. The demo shows their output for a few sample invoices. Licences start at 19 CHF a month for one person; see the package page for all plans.