README

Validate e-invoices against EN 16931 in plain PHP - no Java, no network, no external service.

VAMPIRE PHP takes an XML invoice ( UBL or CII ) and returns a validation report: first well-formedness, then the XML schema, then the business rules of the matching rule set. The rules come from the official Schematron packages; they are executed by an XPath 2.0 interpreter of its own, not by an XSLT processor. Rule identifiers, message texts and the accept / reject decision are those of the reference validator of KoSIT.

What it checks

Rule set	Syntaxes
EN 16931 core rules	UBL, CII
XRechnung 3.0.2, including Extension and CVD	UBL Invoice, UBL CreditNote, CII
Peppol BIS Billing 3.0.21	UBL Invoice, UBL CreditNote
Factur-X / ZUGFeRD 2.5.2, profiles EN16931 and EXTENDED	CII
Factur-X / ZUGFeRD 2.1 to 2.5.2, all profiles, for the check against every edition	CII

A document whose rule set is not in the package gets no verdict and names the missing rule set; it is never reported as rejected by mistake.

Requirements

PHP 8.2 or newer with ext-dom, ext-libxml and ext-bcmath. No other runtime dependencies.

Installation

composer require invoicepress/vampire-php

Usage

use EinvoiceValidator\Pipeline\ScenarioResolver;
use EinvoiceValidator\Validator;

// The package directory: the scenarios decide which schema and which rule sets an invoice gets.
$package   = dirname( ( new ReflectionClass( Validator::class ) )->getFileName(), 2 );
$validator = new Validator(
    scenarioResolver: ScenarioResolver::fromJsonFile( $package . '/rulesets/scenarios.json' ),
    baseDir:          $package,
);

$result = $validator->validateFile( 'invoice.xml' );

echo $result->isAccepted() ? "accepted\n" : "rejected\n";

foreach ( $result->messages() as $message ) {
    printf( "%-8s %-14s %s\n", $message->flag->value, $message->ruleId ?? '-', $message->text );
}

⚠️ baseDir is the package directory, not your project root. The paths inside scenarios.json are resolved against it; pointing it elsewhere resolves the scenario but runs no rules.

validateString() takes the XML as a string and validateDom() a DOMDocument.

Together with horstoeko/zugferd

VAMPIRE PHP checks what horstoeko/zugferd or horstoeko/invoicesuite writes, in the same process and without a detour through a file:

use horstoeko\zugferd\ZugferdDocumentBuilder;
use horstoeko\zugferd\ZugferdProfiles;

$document = ZugferdDocumentBuilder::createNew( ZugferdProfiles::PROFILE_EN16931 );
$document->setDocumentInformation( 'R-2026-001', '380', new DateTime( '2026-10-18' ), 'EUR' );
// … fill in seller, buyer, lines and totals as usual …

$result = $validator->validateDom( $document->getContentAsDomDocument() );

With only the document information above, the result is "rejected", and the first message is BR-06: an invoice shall contain the seller name ( BT-27 ).

Using VAMPIRE with horstoeko/zugferd or invoicesuite

Two small packages put VAMPIRE in the place of the KoSIT validator of the libraries of horstoeko. They need no Java, and changing one class name is enough:

Library	Package	Class
`horstoeko/zugferd`	`invoicepress/vampire-zugferd`	`ZugferdVampireValidator`, used like `ZugferdKositValidator`
`horstoeko/invoicesuite`	`invoicepress/vampire-invoicesuite`	`InvoiceSuiteVampireDocumentValidator`, a validator of invoicesuite like `InvoiceSuiteKositDocumentValidator`

The two packages cannot be installed together, because invoicesuite declares a conflict with horstoeko/zugferd.

Command line

bin/einvoice-validator validate invoice.xml
bin/einvoice-validator validate invoice.xml --format=json
bin/einvoice-validator ruleset:list
bin/einvoice-validator selftest

Exit codes: 0 accepted, 1 rejected, 2 calling error.

Documentation

The manual for users is in docs/manual/ in English and German. The developer documentation in docs/developer/ is in German:

File	Content
`docs/developer/api.md`	the public API, its exceptions, and what counts as internal
`docs/developer/report-formats.md`	the report formats JSON, HTML and KoSIT XML
`docs/developer/profile-format.md`	rule profiles: own rules on top of the official ones
`docs/developer/custom-rules.md`	own rules bound to business terms
`docs/developer/eu-cius.md`	the national variants: what runs and what does not
`docs/developer/performance.md`	run time and memory for large invoices

Development

composer install
composer test

The test suite has 1,341 tests; 29 of them compare against an invoice corpus and recordings outside this repository and are skipped without them ( see tests/Support/Corpus.php ). src/ is the runtime. The rule packages under rulesets/ are compiled from the official Schematron and scenario files; the compiler is not part of this repository.

Licence

VAMPIRE PHP is free software under the GNU General Public License, version 2 or later ( LICENSE ).

The rule packages are not original work of this project. Each one is derived by machine from a published Schematron rule set and carries the licence of its source in its head. NOTICE names origin, rights holder and licence of every rule package, and licences/ holds the licence texts.

invoicepress / vampire-php

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