einvoice-preflight now has an Austria page, the 33rd on its mandate hub. Suppliers to federal bodies have had to invoice electronically since 1 January 2014, and since 18 April 2020 that means EN 16931 invoices through the e-Rechnung.gv.at portal or Peppol, as ebInterface XML or Peppol BIS Billing 3.0. Business-to-business invoicing is voluntary, and the 2027 to 2035 dates some guides print are guesses, not adopted law.
The page says where its facts come from: vendor and guide excerpts read on 2026-10-26, not the legal text or the finance ministry's pages. It also names a real gap. The checker reads UBL, CII, Factur-X and JSON, applies the Peppol rules on request, and does not read ebInterface XML, so an Austrian federal invoice in that format is outside what it can check. Reading ebInterface is the next useful step for this market. Not tax advice.