@invoiceleaf/integration-elster

ELSTER / German Tax integration for InvoiceLeaf. Generates ELSTER-ready USt-Voranmeldung (XML) and EUER (Excel) files for manual upload in Mein ELSTER.

This package is public-mirror safe: it contains only TypeScript that builds XML/Excel. It ships no native code, no certificates, and no ERiC binary. Export-only: it produces files the user uploads themselves; it does not submit to the Finanzamt. (Direct ERiC submission is a separate, later capability.)

Surface

Exports (appear inside the normal export form):

• ustva-xml (exportUstva) — build the USt-VA XML for a period and return it as a downloadable file.
• euer-xlsx (exportEuer) — aggregate a tax year into an Excel workbook.

Actions:

• preview-ustva (previewUstva) — read-only USt-VA figures as JSON. AI-callable.

Config (install-time)

• steuernummer, finanzamt, ustvaPeriod (required) — used to populate the generated files.

Category → form-line mapping

src/mapping/ holds the category → USt-VA Kennzahlen / EUER line scaffold with default tables. Export quality is bounded by this mapping — see the REVIEW REQUIRED notes in src/mapping/lines.ts and src/mapping/index.ts.

Status / TODOs

This is a compiling skeleton. Notable placeholders:

• The USt-VA XML builder (buildUstvaXml) emits a placeholder, schema-invalid document — not yet a valid ELSTER upload.
• The EUER export returns a text placeholder under an .xlsx filename — not a real OOXML workbook.
• The aggregation/mapping defaults need tax review.

See the inline TODO(...) / REVIEW REQUIRED markers for the full list.

Development

npm install
npm run typecheck
npm run build