EInvoice for Pascal

A unified electronic invoicing library for Delphi and Free Pascal supporting XRechnung, ZUGFeRD / Factur-X, Peppol BIS Billing, UBL and CII.

Status: beta, version 0.9.0-beta.1. Reading, writing and checking work for XRechnung 3.0, ZUGFeRD 2.5 / Factur-X 1.09 and Peppol BIS 3.0, and documents are validated against the KoSIT configurations without Java. The API may still change until 1.0; see the CHANGELOG.

Goals

• One library for reading and writing electronic invoices according to EN 16931: XRechnung (UBL and CII), ZUGFeRD / Factur-X (MINIMUM to EXTENDED) and Peppol BIS Billing. MINIMUM and BASIC WL carry no invoice lines; in Germany they do not count as e-invoices since 2025, in France they serve as booking aid. The library writes them on request and leaves the legal judgement to the application.
• One code base for Delphi 6 through Delphi 13 and Free Pascal 3.2.2+ (Windows, Linux, macOS).
• Three levels of access:
  • TLandrixInvoice: the semantic invoice model (business terms BT-... / BG-...), independent of the syntax. This is the model known as TInvoice from XRechnung-for-Delphi.
  • TLandrixCII... and TLandrixUBL...: syntax models generated from the schemas, for everything the semantic model does not cover: CII with everything Factur-X EXTENDED has, UBL with the elements of EN 16931, XRechnung and Peppol (an extensible positive list).
• Validation without Java: documents are checked against the official KoSIT configurations (XML schema and Schematron) natively, with the same verdict as the KoSIT validator, and invoices are shown as HTML or Markdown.
• No dependency on MSXML or other XML libraries: XML is handled by LandrixXML for Pascal, included as a Git submodule.

Quick start

uses
  LandrixEInvoiceTypes, LandrixEInvoiceSpecs, LandrixEInvoiceInvoice, LandrixEInvoice;

// write
TLandrixEInvoice.SaveToFile(Invoice, 'invoice.xml', TLandrixEInvoiceTargets.XRechnung('3.0', esy_UBL));

// read XML or a ZUGFeRD / Factur-X PDF
Doc := TLandrixEInvoice.LoadFromFile('invoice.pdf');
try
  WriteLn(string(Doc.Invoice.InvoiceNumber));
finally
  Doc.Free;
end;

Writing checks the business rules of the target and refuses an invalid invoice (ELandrixEInvoiceWriteError, nothing written).

What is checked

The rule check predicts what the official validator reports for the document the library would write. Each family is compared with an official reference:

Target	Rules	Compared with
all EN 16931 targets	BR-01 to BR-65, BR-CO-..., the VAT category rules BR-S-... to BR-AG-...	KoSIT XRechnung test suite
XRechnung 3.0	BR-DE-..., BR-DEX-09, the code lists BR-CL-01 to BR-CL-26, the PEPPOL-EN16931 rules of its schematron	KoSIT XRechnung test suite
ZUGFeRD / Factur-X 1.09	the EN 16931 rules per profile, BR-FXEXT-... (EXTENDED), the 366 code asserts FX-SCH-A-...	KoSIT validator on the ZUGFeRD examples and mutants
Peppol BIS 3.0.21	the whole Peppol schematron: PEPPOL-EN16931-..., PEPPOL-COMMON-... (identifier check digits), the national rules of DE, DK, GR, IS, IT, NL, NO and SE	OpenPEPPOL unit tests

In all about 380 rule identifiers and the 366 Factur-X code asserts. The check does not replace schema validation; see Checking for the details and the known limits.

Documentation

• Getting started (Deutsch): setup, the three models, targets
• Writing, Reading, Checking
• Validating and showing invoices: the KoSIT files, validation, reports, HTML and Markdown, what to ship
• Moving from XRechnung-for-Delphi, moving from ZUGFeRD-for-Delphi
• Examples: console programs for Delphi (.dpr) and Lazarus (.lpi), including the 24 business cases of XRechnung-for-Delphi, and Workbench, a window (VCL and LCL) to create, open, check and show invoices

Public API

The facade TLandrixEInvoice (unit LandrixEInvoice) reads and writes invoices with one call; the stable units below are covered by semantic versioning from release 1.0 on. Every unit states its level in a comment before its unit line (API: stable or API: internal), and tools/check-forbidden.py checks that the interface of a stable unit uses no internal unit.

• Stable: LandrixEInvoice (facade, documents, exceptions), LandrixEInvoiceTypes, LandrixEInvoiceInvoice, LandrixEInvoiceCodes, LandrixEInvoiceDiagnostics, LandrixEInvoiceSpecs, LandrixEInvoiceCII and LandrixEInvoiceUBL (syntax models), LandrixEInvoicePdf, LandrixEInvoiceCompatXRechnung, LandrixEInvoiceCompatXRechnungAdapter, LandrixEInvoiceCompatXRechnungPdf.
• Preview (marked API: internal, documented in Validating; names may still change before 1.0): LandrixEInvoiceValidator, LandrixEInvoiceValidation, LandrixEInvoiceValidationReport, LandrixEInvoiceValidationHtml, LandrixEInvoiceReportHtml, LandrixEInvoiceRenderHtml, LandrixEInvoiceRenderMarkdown.
• Internal (may change in any release): LandrixEInvoiceMapCII, LandrixEInvoiceMapUBL, LandrixEInvoiceCheck, LandrixEInvoiceCheckPeppol, LandrixEInvoiceIdentifiers, LandrixEInvoiceCodeNames, LandrixEInvoiceRenderLabels, LandrixEInvoiceRender, LandrixEInvoiceRenderWalk, LandrixEInvoiceRules, LandrixEInvoiceCalc, LandrixEInvoiceSubLines, LandrixEInvoicePdfObjects, LandrixEInvoicePdfCheck, LandrixEInvoiceLexical, LandrixEInvoiceFiles, LandrixEInvoiceCIIProfiles, LandrixEInvoiceCIICodeRules, and the readers and writers LandrixEInvoiceCIIReader, LandrixEInvoiceCIIWriter, LandrixEInvoiceUBLReader, LandrixEInvoiceUBLWriter. What they offer for reading, writing, checking and calculating is reachable through the facade.

Getting the sources

git clone --recurse-submodules https://github.com/LandrixSoftware/EInvoice-for-Pascal.git

For an existing clone: git submodule update --init.

Related projects

XRechnung-for-Delphi and ZUGFeRD-for-Delphi remain available and maintained. EInvoice-for-Pascal combines their functionality in one library.

License

EInvoice-for-Pascal is dual-licensed.

You may use the software under either:

• GNU General Public License version 3 or later; or
• the Landrix Software Commercial License.

The commercial license permits integration and distribution as part of proprietary applications without the copyleft requirements of the GPL. See COMMERCIAL-LICENSE.md.

Third-party components are listed in THIRD-PARTY-NOTICES.md.

Contributing

Contributions are welcome. Please read CONTRIBUTING.md first; it explains the licensing terms for contributions and the language rules that keep the code compatible with Delphi 6. Security issues: see SECURITY.md.