1. Background   In July 2018, Hungary introduced a real-time invoice reporting (RTIR) model, whereby each taxable entity shall perform data reporting for each invoice to the National Tax and Customs Authority's (NAV) platform Online Szamla.   2. CTC model overview   Under the RTIR model, e-invoicing is not strictly regulated. Still, the supplier must report a subset of the invoice to the tax agency in a predefined format shortly after issuance and distribution to the buyer. NAV will validate each transaction and either accept or reject it.   3. Technical requirements   The section below outlines the most important...