Since January 1, 2026, every VAT-liable business in Belgium must send and receive structured electronic invoices via the Peppol network for domestic B2B transactions. For large enterprises already connected through B2G e-invoicing via Mercurius, this was a natural extension. But for Belgium's hundreds of thousands of SMEs, it's a significant shift.
If you're an SME still figuring this out — or if you've started but are running into issues — this guide walks you through every step. No jargon, no assumptions. Just practical advice to get you from PDF invoices to Peppol compliance.
Understanding Your Obligations
Not every invoice must go through Peppol. The mandate is specific about scope. Understanding exactly which invoices are covered will save you time and prevent unnecessary complexity.
- B2B invoices between two Belgian VAT-registered businesses
- Credit notes related to domestic B2B transactions
- Invoices issued by Belgian branches of foreign companies (if VAT-registered in Belgium)
- B2C invoices (business to consumer)
- Cross-border invoices (Belgian company to foreign company)
- Invoices to/from non-VAT-registered entities
- B2G invoices (already handled via Mercurius)
In practice, if you invoice other Belgian businesses for goods or services and charge Belgian VAT, those invoices must go through Peppol. It's that straightforward.
Choosing a Peppol Access Point
A Peppol Access Point (AP) is the service that connects your business to the Peppol network. Think of it as your "email provider" for invoices. You need one to send and receive Peppol documents.
Your AP must be certified by OpenPeppol. You can verify this on the OpenPeppol directory. InvoStaq is a certified AP operating across the EU.
Choose an AP that specifically supports Belgian businesses — understanding Belgian VAT rules, BOSA requirements, and local accounting software integrations.
Ensure the AP integrates with your accounting software. Many APs offer pre-built connectors for ClearFact, Octopus, Yuki, Exact, and Horus.
Most APs offer SME-friendly pricing: per-document fees (€0.10–0.50 per invoice), monthly subscriptions (€29–99/month), or bundled packages. Avoid APs that require long-term contracts.
The best APs provide guided onboarding, test environments, and dedicated support during your first weeks. Don't choose the cheapest option if it means zero support.
Connecting Your Accounting Software
The connection method depends on your accounting software. Belgian SMEs typically use one of the following platforms, each with different Peppol integration approaches:
ClearFact
Built-in Peppol module since v12.3. Enable in Settings → E-Invoicing → Peppol.
Octopus
Peppol connector available from December 2025. Requires Octopus Online subscription.
Yuki
UBL 2.1 export with automatic Peppol routing. Supported for all Belgian entities.
Exact Online
Connect through your Access Point's API. InvoStaq offers a pre-built Exact connector.
Horus
Export UBL 2.1 files and route through your Peppol Access Point for transmission.
SAP / Dynamics 365
Native Peppol modules available. InvoStaq provides managed integration for mid-market deployments.
If your software has native Peppol support, activation is usually as simple as entering your Peppol Participant ID and selecting your Access Point in the settings. For software that requires AP integration, your AP provider (like InvoStaq) will provide API credentials and guide you through the setup.
What's a Peppol Participant ID?
Your Peppol Participant ID is how other businesses find you on the Peppol network. In Belgium, it's typically based on your Enterprise Number (KBO/BCE) prefixed with the Peppol identifier scheme (0208). Your Access Point will register this for you during onboarding.
Testing Your First E-Invoices
Before you start sending real invoices via Peppol, you should run tests. A good Access Point provides a test environment where you can send invoices without them reaching actual recipients.
Validate UBL Structure
Ensure your invoices conform to UBL 2.1 and Peppol BIS 3.0. Your AP's validation engine will flag structural errors.
Check Mandatory Fields
Belgian Peppol invoices require: seller/buyer VAT numbers, invoice date, line items with unit prices, VAT breakdown, and payment terms.
Test Receiver Lookup
Verify that your trading partners are registered on the Peppol SML/SMP. If not, they may need to register through their own Access Point first.
Verify Delivery Receipts
Peppol provides delivery receipts (MDN). Confirm that your system captures and stores these as proof of successful transmission.
InvoStaq's test environment includes a Traffic Light Protocol that gives instant Green / Amber / Red feedback on every test invoice. Green means ready to send. Amber means minor issues that should be fixed. Red means the invoice would be rejected by the network.
Common Mistakes to Avoid
Based on our experience onboarding hundreds of Belgian SMEs since January, these are the most frequent pitfalls:
Peppol invoices are structured XML (UBL 2.1), not PDFs. If you're attaching a PDF to an email, that's not a Peppol invoice. Your accounting software should generate the UBL file automatically.
Double-check your Peppol Participant ID and your trading partner's ID. A wrong ID means the invoice can't be delivered. Ask your AP to verify lookups.
Belgian VAT numbers must follow the BE0XXXXXXXXX format. Ensure no spaces, dashes, or missing country prefix. This is the most common single validation error.
Each invoice line must include a description, quantity, unit price, VAT rate, and line total. Missing any of these will trigger a Peppol BIS validation error.
Older versions of ClearFact, Octopus, and Yuki don't support Peppol. Update to the latest version before attempting to connect.
Cost Considerations
One of the biggest concerns for SMEs is cost. The good news is that Peppol Access Points offer SME-friendly pricing that is often comparable to — or even cheaper than — the cost of printing and mailing paper invoices.
Per-Document
€0.10–0.50
per invoice sent/received
Ideal for low-volume SMEs processing fewer than 100 invoices per month.
Monthly Subscription
€29–99
per month, includes volume
Best for mid-volume SMEs. Typically includes 200–1,000 invoices per month.
Bundled Package
Custom
AP + software + support
Some APs bundle Peppol connectivity with accounting software and onboarding support.
Consider the hidden costs of not complying: penalties from July 2026, lost business from partners who require Peppol invoices, and the ongoing cost of manual PDF processing. Most SMEs find that Peppol compliance pays for itself within 3–6 months through reduced administrative overhead.
Government Support & BOSA Resources
The Belgian government, through BOSA (Federal Public Service Policy & Support), provides several resources to help SMEs transition:
BOSA E-Invoicing Portal
Official guidance, FAQs, and documentation for the B2B Peppol mandate. Available in Dutch, French, German, and English.
Free SME Webinars
BOSA runs regular free webinars (in Dutch and French) walking SMEs through Peppol onboarding basics. Registration via the BOSA website.
Dedicated SME Helpdesk
A dedicated helpdesk for small businesses struggling with the transition. Available via phone and email during business hours.
Micro-Enterprise Subsidies
Micro-enterprises (fewer than 10 employees, under €2M turnover) may qualify for subsidised Access Point connections in certain regions.
How InvoStaq Makes Onboarding Simple
InvoStaq is a certified Peppol Access Point with dedicated Belgian SME onboarding packages. Here's what sets our approach apart:
1-Week Onboarding
Most SMEs are live on Peppol within one week. We handle Participant ID registration, software connection, and initial testing.
Pre-Built Connectors
Ready-made integrations for ClearFact, Octopus, Yuki, Exact, and Horus. No custom development required for standard setups.
AI-Powered Validation
Every invoice is validated in real-time against Peppol BIS 3.0 rules. Our Traffic Light Protocol gives instant pass/fail feedback.
Dedicated Belgian Support
Dutch and French-speaking support team based in the EU. Available by phone, email, and chat during Belgian business hours.
Whether you process 10 invoices a month or 10,000, InvoStaq scales with your business. Our SME packages start with transparent, per-document pricing with no long-term contracts — so you can start small and grow.
Ready to Get Your SME on Peppol?
InvoStaq's Belgian SME onboarding package gets you compliant in as little as one week — with dedicated support every step of the way.