What is CTC? Continuous transaction controls and the five-corner model explained

Updated 22 October 2026. This article was first published in 2022. It now reflects the CTC models in use in 2026 and the EU’s ViDA rules.

Continuous transaction controls (CTC) give tax authorities access to invoice data when a transaction happens, instead of in a later audit. Countries use different models. In some, the tax authority must clear each invoice before it counts as issued. In others, invoice data is reported shortly after the invoice is sent. A growing number use a decentralized model, where certified service providers exchange the invoice and report the tax data. In the EU, ViDA makes digital reporting mandatory for cross-border B2B transactions from 1 July 2030.

Clearance models started in Latin America. In Brazil, an electronic invoice (NF-e) is only valid once the tax authority has received it before the taxable event. Mexico requires CFDI electronic invoices, in version 4.0 since 2022. In Europe, Italy introduced general B2B clearance in 2019.

In the Peppol four-corner model, the seller (C1) sends the invoice through its service provider (C2) to the buyer’s service provider (C3), which delivers it to the buyer (C4). In OpenPeppol’s CTC model, the tax administration or its designated service provider becomes C5. C2 and C3 send Tax Data Documents with the relevant invoice data to C5, while the invoice itself continues to flow between the parties.

OpenPeppol calls this “Decentralised Continuous Transaction Controls and Exchange” (DCTCE). It is described in the Peppol CTC Reference Document (2021) and its 2023 addendum. There is no single global Peppol CTC specification. Instead, Tax Data Document specifications are published per country, currently for the UAE, Slovakia, and Oman. OpenPeppol is also running a ViDA pilot, started in November 2024, to test the model for EU digital reporting.

For country requirements in more detail, see our complete country list and the step-by-step guides for France, Slovakia, and the UAE.

ViDA introduces digital reporting requirements for cross-border B2B transactions within the EU from 1 July 2030, based on structured e-invoices that follow EN 16931. Member states may introduce domestic e-invoicing and reporting, and those that had real-time reporting in place before 2024 must align their systems with the EU model by 1 January 2035. Read more in ViDA explained: VAT in the Digital Age timeline and what to do before 2030.

Qvalia is a certified Peppol Access Point and is certified for Slovakia’s eFaktúra framework, which uses the five-corner model. Review Qvalia’s Peppol and e-invoicing country coverage or read the short summary What are CTC models? in our knowledge base.

Sources: Peppol CTC Reference Document, Addendum, Council Directive (EU) 2025/516, and the national tax authority sites linked from our country guides.