Greece is moving from voluntary e-invoicing to a fully mandatory framework for business-to-business (B2B) transactions. The obligation was formally established with Law 5222/2025, complementing existing e-Bookkeeping (myDATA) and B2G e-invoicing requirements. The system is overseen by the Independent Authority for Public Revenue (AADE) and is aligned with the European standard EN 16931.
Timeline
The rollout follows a phased approach:
- 1 February 2026: Mandatory for large taxpayers whose annual turnover exceeded EUR 1 million in the 2023 fiscal year.
- 1 October 2026: Extended to all remaining businesses established in Greece.
- Exemptions: A limited group of digitally excluded taxpayers will be allowed to remain outside the system.
Scope
The B2B mandate applies to all domestic transactions between Greek VAT-registered businesses, as well as certain cross-border supplies. Invoices issued under this system must be structured electronic documents rather than PDFs or paper invoices. The goal is to ensure real-time tax reporting and to reduce compliance gaps by integrating invoicing with AADE’s digital systems.
Submission and Process
Businesses will issue and transmit invoices through either:
- Certified e-invoicing service providers or
- AADE’s platforms for smaller taxpayers without provider access.
Each invoice will be validated by AADE before reaching the recipient, creating a clearance-style process that ensures authenticity, integrity, and immediate reporting.
Technical Details
Invoices must follow the EN 16931-compliant XML format. Transmission is handled via AADE’s APIs or certified service providers, with strict requirements for digital archiving, integrity checks, and audit trails. Attachments may be transmitted using extended schema features, and AADE will release detailed technical specifications and testing environments to support implementation.
How can SNI help you?
SNI’s Greece e-Invoicing solution is an end-to-end package that covers every stage of compliance with the new B2B mandate. Within SAP, users can retrieve financial data, perform automated data mapping, and generate invoices in the required EN 16931-compliant XML format. The user-friendly SNI Cockpit allows key users to monitor, validate, and manage all transactions, ensuring accuracy and control at every step.
Submission is performed via accredited e-invoicing service providers, ensuring compliance with the clearance process before invoices are delivered to the recipient. For inbound invoices, issued by suppliers to clients, the solution automatically retrieves data at regular intervals using the APIs and web services available through the accredited channels, giving users real-time access to validated supplier invoices.
All inbound invoices are displayed in SNI’s dedicated Inbound Cockpit, designed for an optimal user experience. Invoices can be viewed in both XML and human-readable PDF/HTML formats, ensuring transparency and compliance with regulatory standards. In addition, SNI’s invoice reconciliation feature automatically matches incoming invoices against purchase orders, delivery notes, or other internal documents, minimizing errors and reducing manual effort while improving efficiency.
SNI’s Greece e-Invoicing solution integrates with clients’ existing systems without requiring upgrades or changes. It is fully compatible with SAP ECC 4.7 and above, SAP R/3, SAP S/4HANA, and SAP Business Technology Platform (BTP). Beyond SAP, SNI also offers ERP-independent solutions that integrate seamlessly with any ERP environment, enabling businesses across industries to stay compliant with the Greek B2B mandate.
