E-invoicing for Indian companies: GST e-invoicing at home, Peppol for the EU

01GST e-invoicing in India

Under GST e-invoicing, a GST-registered business with aggregate annual turnover above ₹5 crore reports its B2B invoices, and its export invoices, to the Invoice Registration Portal (IRP). The IRP registers each invoice and returns an Invoice Reference Number (IRN); the current threshold has applied since 1 August 2023. Since 1 April 2025, larger businesses also face a time limit: an invoice more than 30 days old can no longer be reported on the IRP, so the reporting step has to run close to the moment of invoicing.

This is a reporting model: the business keeps issuing invoices from its own ERP, and the IRP registers each one and sends back the IRN. The obligation attaches to an Indian GST registration. A European company without one is not affected, and it does not reach invoices that a European subsidiary issues under its own VAT registration.

For an Indian business the effort sits in the ERP integration: correct GST registration numbers and tax classifications in master data, a call to the IRP for each invoice, the IRN stored with the invoice, and a routine for rejections that clears them before the 30-day window closes.

02Belgium’s B2B obligation since January 2026

In the EU, Belgium is the clearest example for an Indian group with a Belgian subsidiary. Its law of 6 February 2024 changed the VAT Code and the 1992 Income Tax Code so that, from 1 January 2026, domestic invoices between businesses must be structured e-invoices; royal decrees then settled the technical detail and the penalties. Practical guidance is on the federal e-invoicing portal (opens external site), which FPS BOSA runs with FPS Finance.

FPS Finance kept the start date but allowed a grace period for the first quarter of 2026: a business that could show it had taken reasonable steps in good time faced no penalty for breaching the new rules. The grace period closed on 31 March 2026. Fixed penalties can now be imposed: EUR 1,500 when the technical means to send and receive e-invoices are missing, EUR 3,000 for a second breach and EUR 5,000 for every further one.

The Belgian rule covers VAT-registered businesses established in Belgium when they invoice one another for transactions located in the country; cross-border invoices are not yet included. Out of scope are foreign businesses with no fixed establishment in Belgium, businesses making only supplies exempt under Article 44 of the VAT Code, and businesses in bankruptcy. An Indian parent with no fixed establishment in Belgium that invoices a Belgian customer directly therefore stays outside the rule, while its Belgian subsidiary falls inside it. Belgian public bodies receive their invoices through Mercurius, a government platform linked to Peppol.

Belgium intends to add e-reporting next, sending invoice data to the tax administration as well from 1 January 2028. When this article was written, the law for that step was not yet final.

03What an e-invoice means in the EU

In the EU, “e-invoice” means structured data: a file that a machine can read and process without human interpretation, following the semantic data model of the European standard EN 16931. PDFs, scanned paper and word-processor files do not count, even when emailed. A readable PDF may travel with the structured file, but legally the data is the invoice.

That differs from the Indian set-up. Under GST, the seller reports invoice data to the IRP and receives an IRN in return; under Peppol, the invoice itself travels from the seller’s system to the buyer’s system in a standard format. Different formats over different routes mean the ERP needs a separate output for each.

Belgium’s default is the Peppol network, with invoices in Peppol BIS Billing 3.0, Peppol’s implementation of EN 16931 in UBL syntax. Two businesses may use another network or format if the invoice still conforms to EN 16931; in practice, Belgian customers and suppliers will expect Peppol.

04How Peppol works

Peppol combines an international network with document specifications, managed by OpenPeppol, a non-profit association in Brussels. Four parties handle each invoice: the seller’s ERP passes it to the seller’s access point, that access point delivers it to the buyer’s access point, and the buyer’s access point hands it to the buyer’s ERP. Before sending, the seller’s access point queries the Service Metadata Locator, the network’s address book, which points to a Service Metadata Publisher holding the receiver’s registration and the document types it accepts.

The practical consequence is that one agreement with one access point provider reaches every registered company on the network, whichever provider they have chosen. A Belgian company is usually identified on Peppol by its enterprise number. Many ERP and accounting products include an access point, and specialist providers serve high volumes and further document types such as purchase orders and credit notes.

• Registration: your company appears in the directory with its identifier and the documents it accepts; an absent or incorrect entry is a common cause of invoices that never reach you.
• Validation: each access point checks invoices against the Peppol BIS Billing 3.0 rules and rejects any that fail before they reach the buyer.
• Delivery status: the network only confirms technical delivery. Whether the buyer accepts, disputes or pays is a separate business message, available only if both parties support it.

05The EU framework and the road to 2030

Two EU instruments shape the national rules. Under Directive 2014/55/EU (opens external site), public contracting authorities must accept e-invoices that follow EN 16931, which explains why invoicing to governments went electronic first across most of the Union. ViDA, the VAT in the Digital Age package, with Council Directive (EU) 2025/516 (opens external site), was adopted in March 2025 and has been in force since 14 April 2025. Since then Member States can impose domestic e-invoicing without asking the EU for a derogation. Intra-EU B2B supplies move to mandatory e-invoicing and digital reporting from 1 July 2030, and national real-time reporting systems have until 1 January 2035 to converge on the EU model.

Until 2030, every Member State chooses its own timing and design: some rely on Peppol, some on a national platform that clears each invoice, some on both. For an Indian group with companies in several EU countries, that means one integration design with several outlets, on top of the IRP at home.

06One ERP, two outlets: where projects succeed or stall

Registering a first invoice on the IRP, or sending a first one over Peppol, is quick. Running every invoice through both without manual touches is a design exercise, and the hard parts are master data, checks before sending, incoming invoices and archiving, not the networks themselves.

• Master data first. Indian customers need a correct GST registration number and tax classification; European customers need the right Peppol identifier, VAT number and address; every item needs units and tax categories that map to what each format expects. Confirm that a European customer is on Peppol before the first invoice, and recheck regularly, because companies move between providers.
• Check before you submit. Run the IRP’s checks and the Peppol BIS rules inside your own process, so an invoice that would bounce is fixed in the ERP instead of surfacing weeks later, or after the IRP’s 30-day window has shut.
• Design the inbound flow. Structured invoices, and Indian supplier invoices that carry an IRN, can be reconciled automatically with the vendor, the PO and the GRN, so that an approver only sees exceptions. That is where most of the savings come from. Paper or PDF invoices, for example from smaller suppliers, can join the same flow through document intelligence.
• Preserve the originals. The structured file sent or received, and the IRN record for Indian invoices, are evidence. Store them unaltered, with proof of delivery, for as long as each country’s law requires, and keep them retrievable and readable for auditors.
• Watch the pipeline. IRP rejections, failed Peppol deliveries and invoices stuck in approval should sit on a dashboard that someone owns, not in a shared inbox.

Odoo localisations differ by country; the Belgian one sends and receives over Peppol, so most of the work there is setup, master data and approval rules. In SAP environments the choice is normally SAP’s own e-document compliance tools or a connection to an external access point or reporting provider, and either option needs the same discipline on data and errors. When several ERPs, an online store and a group system all issue invoices, one integration layer can hold formats, checks and monitoring centrally for the IRP and for Peppol alike.

07A practical plan

1. 01List every invoicing flow. Which systems send and receive invoices and credit notes, in India and in each EU country, and by which channel, including online stores, subscription billing and intercompany invoices between the Indian parent and its EU subsidiaries.
2. 02Pick the connection model. Your ERP’s own connectors, a specialist provider, or one integration layer for several systems, chosen on volumes, document types and countries.
3. 03Fix the master data. GST registrations, Peppol identifiers, VAT numbers, units and tax categories for customers, vendors and items.
4. 04Pilot with real counterparties. Swap test invoices with your biggest customers and vendors before the switch, and see how their systems treat yours.
5. 05Automate inbound processing. Matching, approval and booking, with exceptions routed to finance staff under maker-checker.
6. 06Archive and monitor. Keep structured originals, IRNs and proof of delivery, and give every failed message an owner.
7. 07Get ready for reporting. Shape the data flows now so that invoice data can reach tax administrations as e-reporting starts in Belgium and elsewhere in the EU.

08Developments to follow

• GST notifications and IRP advisories that change scope or timelines in India.
• The Belgian e-reporting law and its technical specifications, expected for 1 January 2028.
• Each Member State’s transposition of ViDA, and which ones bring domestic transactions under the 2030 rule.
• Progress in France and Spain, the end of Germany’s transition periods in 2027 and 2028, and new Peppol BIS Billing 3.0 releases and validation rules.

E-invoicing rules are changing in India and in almost every EU country. Put a date on each internal note and re-read the official portals whenever a design choice depends on them.