When Belgium mandated Peppol-based B2B e-invoicing from January 1, 2026, the headline was about digital invoicing. But the deeper story is about VAT modernisation. By requiring all domestic VAT-liable transactions to flow as structured electronic documents, Belgium has laid the foundation for a fundamentally different approach to tax collection.
This article explores the VAT gap problem that drives this reform, how structured e-invoices enable automated VAT data collection, the path from Belgium's current Peppol mandate to continuous transaction controls (CTC), and what businesses should expect in the coming years.
The VAT Gap Problem
The VAT gap — the difference between expected VAT revenue and what's actually collected — is one of the EU's most persistent fiscal challenges. According to the European Commission's latest report, the EU-wide VAT gap exceeded €61 billion annually. Belgium's share, while proportionally moderate compared to some Member States, still represents billions in lost revenue.
€61B+
EU-Wide VAT Gap
Annual difference between expected and collected VAT revenue across all 27 EU Member States.
~12%
Average Gap Rate
The EU average VAT gap rate, though significant variation exists between Member States.
€2.4B
Belgium Estimate
Belgium's estimated VAT gap contribution, driven by underreporting, errors, and fraud.
The VAT gap arises from multiple sources: deliberate tax fraud (carousel schemes, missing trader fraud), unintentional errors in VAT returns, insolvencies, and administrative inefficiencies. Traditional post-audit approaches — where tax authorities review VAT returns months or years after the fact — simply cannot keep pace with the scale of the problem.
How Structured E-Invoices Enable VAT Data
The critical difference between a PDF invoice and a structured Peppol invoice (UBL 2.1) is machine readability. A PDF is essentially a picture of an invoice — a human can read it, but a computer cannot reliably extract data from it. A UBL 2.1 invoice, by contrast, is a structured XML document where every data point is tagged, validated, and queryable.
Tax authority can automatically cross-reference both parties, detecting mismatches or unregistered entities instantly.
Enables automated validation that the correct VAT rate is applied for each product/service category. Catches rate misapplication errors.
Allows automatic aggregation across all invoices to cross-check against VAT return totals. Identifies underreporting immediately.
Ensures invoices are reported in the correct VAT period. Prevents timing manipulation used in some fraud schemes.
Structured payment data enables future cash-accounting VAT models where VAT is only due when payment is received.
In essence, Belgium's Peppol mandate transforms every B2B invoice from an opaque document into a structured data asset that can be analysed, cross-checked, and audited automatically. This is the foundation upon which all future VAT modernisation builds.
From Paper to Real-Time Reporting
Belgium's journey follows a clear evolutionary path. Understanding where Belgium sits today — and where it's heading — helps businesses plan their compliance investments wisely.
Belgium is currently at the "Structured E-Invoice" stage. The Peppol mandate ensures all domestic B2B invoices are in UBL 2.1 format, machine-readable and validated. The next stages — automated VAT data extraction and real-time reporting — are logical progressions that Belgium's infrastructure is now ready to support.
From Peppol to Continuous Transaction Controls
The EU's VAT in the Digital Age (ViDA) directive, targeting implementation from 2028, will require Member States to implement Digital Reporting Requirements (DRR) for intra-EU transactions. Belgium's Peppol mandate positions it ahead of most Member States for this transition.
Belgium's current model is a "post-audit" approach. Invoices flow between businesses via Peppol, but the tax authority doesn't see them in real-time. The structured data is available for audit on request.
The next logical step is for Belgian tax authorities to access aggregated Peppol data — even without clearance — to cross-check VAT return totals against actual invoice volumes. This could be implemented without changing the Peppol infrastructure.
With all invoice data in structured format, Belgium could offer pre-filled VAT returns — similar to pre-filled income tax returns. Businesses would review and confirm rather than manually compile data.
The ultimate evolution is continuous transaction controls (CTC), where invoices are validated or cleared by the tax authority before reaching the recipient. Italy's SdI model demonstrates this approach. Belgium's Peppol infrastructure could evolve to include a government gateway.
Why Peppol Makes CTC Easier
Unlike countries that must build clearance infrastructure from scratch, Belgium already has universal structured e-invoicing via Peppol. Adding a government gateway to the existing 4-corner model is architecturally simpler than retrofitting a proprietary system. The Peppol framework was designed with this extensibility in mind.
How Other Countries Compare
Belgium's approach is distinct from the clearance models adopted by Italy and Spain. Each approach has trade-offs in terms of business impact, VAT gap reduction speed, and implementation complexity:
Italy — SdI
Clearance model via Sistema di Interscambio (SdI). All invoices must pass through the government platform before reaching the recipient.
VAT gap reduced by €3.5B+ in the first two years. Real-time VAT data collection enabled.
Spain — Verifactu
Anti-fraud system requiring certified billing software that stamps invoices with a QR code and reports to the tax authority in near real-time.
Expected to significantly reduce Spain's €5B+ VAT gap through transaction-level visibility.
Belgium — Peppol
Peppol as common denominator for B2B. Not a clearance model (yet), but structured data enables future CTC evolution.
Structured UBL data provides the foundation for automated VAT cross-checking without requiring real-time clearance initially.
Italy's SdI clearance model has proven highly effective at reducing the VAT gap, but it imposed significant operational burden on businesses. Belgium's Peppol-first approach is less disruptive initially while still creating the data infrastructure needed for future CTC evolution. It's a deliberate "crawl, walk, run" strategy.
Belgium's Next Steps
Based on BOSA's published roadmap, BPA communications, and the EU ViDA timeline, here are our predictions for Belgium's VAT modernisation trajectory:
2026–2027: Data Analytics Phase
Belgian tax authorities will begin analysing aggregated Peppol data to identify VAT return discrepancies. No new mandates, but increased audit efficiency using structured invoice data.
2027: E-Ordering via Peppol
BOSA has signalled that Peppol-based e-ordering and e-procurement for B2B transactions will be encouraged, building on the existing Peppol infrastructure investment.
2028: ViDA DRR Compliance
When the EU ViDA directive mandates digital reporting for intra-EU transactions, Belgium will already have the infrastructure in place. Cross-border Peppol invoices will need to be reported.
2029–2030: Pre-Filled VAT Returns
Predicted timeline for Belgium to offer pre-filled VAT returns based on Peppol invoice data. This would dramatically simplify VAT compliance for SMEs.
The timeline suggests Belgium will progressively tighten the feedback loop between invoice data and VAT reporting over the next 3–5 years. Businesses that invest in proper Peppol compliance now are building the foundation for a significantly simpler VAT future — while those who delay face compounding compliance costs.
How to Prepare Now
Whether you're already compliant with the B2B Peppol mandate or still in transition, here's how to position your business for Belgium's evolving VAT landscape:
Ensure Data Quality Now
The accuracy of your structured invoice data matters more than ever. Correct VAT numbers, proper rate classification, and complete line items will become the basis for automated tax checks.
Extend Peppol Cross-Border
Cross-border Peppol invoicing will be included in ViDA DRR. Start using Peppol for EU trade now to build operational maturity before it becomes mandatory.
Automate VAT Reconciliation
With all invoice data in structured format, automate your own VAT return preparation. Match purchase and sales invoices against VAT returns in real-time.
Choose a Forward-Looking AP
Your Access Point should support not just today's Peppol requirements but future CTC evolution. InvoStaq's architecture is built for progressive regulatory change.
InvoStaq's platform is designed with this evolution in mind. As a certified Peppol Access Point, we don't just handle today's B2B mandate — we're building the infrastructure for CTC readiness, ViDA compliance, and automated VAT reconciliation. When Belgium's next regulatory step arrives, InvoStaq customers will already be prepared.
Future-Proof Your Belgian VAT Compliance
InvoStaq's Peppol platform is built for Belgium's evolving VAT landscape — from today's B2B mandate to tomorrow's CTC requirements.