Short answer
If you run SAP S/4HANA in Slovakia, Melasoft offers two routes to send and receive Peppol e-invoices: an SAP e-invoicing add-on that works inside SAP, or a SaaS e-invoicing portal outside SAP.
For S/4HANA users who want an integrated workflow, the SAP add-on is usually the better fit: invoices are created, validated and tracked inside SAP, while the Peppol access point handles delivery and the applicable tax-reporting flow. Below we compare both options and explain how to choose.
Quick context
- Deadline: the mandate starts on 1 January 2027 for in-scope domestic B2B and B2G transactions. Issuing obligations apply to VAT payers, while receiving obligations cover taxable businesses more broadly. The 2026 voluntary phase is an opportunity for testing.
- Format and channel: Peppol BIS Billing, based on UBL 2.1 and EN 16931, exchanged through a certified delivery provider — the “Digital Postman” — meeting Slovak requirements.
- Reporting: the solution must support the applicable Slovak Tax Data Document (SK TDD) reporting flow to the Financial Administration.
Your options
Both routes can support compliance when configured for the applicable Slovak requirements. They differ in how much of the work stays inside SAP.
| Option | How it works | Best for | Watch out for |
|---|---|---|---|
| SAP add-on + Peppol access point | An add-on inside SAP creates, validates and tracks invoices; the access point delivers them and handles the applicable Tax Data Document reporting. | S/4HANA users who want an integrated SAP workflow. | Needs an implementation project with your SAP team. |
| SaaS portal | Invoices are created, sent and received in a cloud-based SaaS portal. | Very low volumes or a quick start. | Without SAP integration, manual work and no automatic posting in SAP. |
Option 1: SAP add-on with a Peppol access point (recommended)
The Melasoft SAP add-on is installed in your SAP system. It converts SD and FI billing documents into Peppol BIS UBL, validates them before sending, and shows invoice statuses in SAP. Invoices travel through your SAP PI/PO or CPI integration to Docnova, Melasoft’s certified Peppol access point, for delivery and the applicable Tax Data Document reporting flow. The implementation must be matched to your S/4HANA deployment and Slovak provider requirements.
- Pros: users stay in SAP screens; errors are caught before sending; supplier invoices arrive in SAP for checking and posting.
- Cons: needs an implementation project with your SAP team.
Option 2: Docnova SaaS portal
Invoices are created, sent and received in the Docnova SaaS portal in the cloud. This standalone route has no SAP integration.
- Pros: no SAP integration project; quick to start.
- Cons: manual work and no automatic posting in SAP in the standalone setup.
How to choose
- Want e-invoicing inside SAP, with integrated invoice creation and posting? Choose the SAP add-on.
- Very few invoices, or need to start quickly? Begin with the SaaS portal.
How the Melasoft SAP add-on and Docnova work together
Melasoft’s SAP add-on keeps invoice operations inside SAP, while Docnova provides the Peppol access-point connection for delivery and the configured Slovak tax-reporting flow.
Outbound invoices. A billing document created in SAP SD or FI is converted by the add-on into Peppol BIS UBL and validated against Slovak rules, invoice types, format and mandatory data. It then travels through SAP PI/PO or CPI to Docnova, which delivers it over Peppol to the buyer’s provider and supports Tax Data Document reporting to the Financial Administration.
Inbound invoices. Supplier e-invoices arrive in Docnova over Peppol, are validated, and flow back into SAP, where the add-on presents them for checking and posting.
What your team sees in SAP:
- Outbound Invoice Cockpit: monitor (HTML, XML, PDF), control, send, check status, download, email and add attachments.
- Inbound Invoice Cockpit: view, check status, download and process supplier invoices inside SAP.
- Periodic programs: run on a schedule to update statuses automatically.
- Custom programs and tables: adapt the solution to your company structure.
Supported business scenarios include sales invoices, credit notes, debit notes, prepayment invoices and self-billing invoices, with document mapping and testing agreed during implementation.
Checklist before 1 January 2027
Use the 2026 voluntary phase to test early and fix issues before the mandate starts.
- List every SAP billing and receiving document type used for Slovak entities.
- Clean master data: buyer DIČ, VAT IDs, addresses, VAT codes and bank details.
- Choose your route: SAP add-on or SaaS portal.
- Select a certified Slovak Digital Postman and confirm the relevant accreditation and reporting scope.
- Register your Peppol ID using the applicable Slovak identifier scheme and check that your main customers and suppliers are reachable with the Peppol ID Checker.
- Map and test outbound invoices, credit notes and corrective invoices.
- Test inbound receipt and posting in SAP.
- Agree a process for technical rejections and accounting corrections; these do not always require the same action.
- Set up invoice archiving for the applicable retention period, including the required XML and audit trail.
- Go live in the voluntary phase and monitor the first weeks closely.
FAQ
Which option is fastest to start? The standalone SaaS portal, because it needs no SAP integration project. The SAP add-on takes longer to set up, but then invoice creation, delivery and processing can run through an integrated SAP workflow.
Do I need SAP DRC to send Peppol invoices? SAP DRC is not required for the Melasoft add-on route. An SAP add-on connected to a Peppol access point can provide an alternative. Confirm compatibility with your S/4HANA edition, deployment and Slovak requirements during implementation.
Can SAP S/4HANA send Peppol invoices to Slovakia? Yes, with an appropriate integration to a Peppol access point, such as the Melasoft SAP add-on with Docnova, configured and tested for the Slovak rules.
What happens if an e-invoice is rejected? Check the rejection reason and whether it is a technical delivery/validation failure or a correction to an already issued invoice. A technical failure may require corrected data and resubmission; an accounting correction may require a credit note or corrective invoice under the applicable rules. Preserve the audit trail rather than deleting issued invoices.
Get compliant before 2027
Melasoft runs Docnova as a certified Peppol access point and offers an SAP add-on for e-invoicing. If you run SAP S/4HANA in Slovakia, we can review your SAP scenario, confirm the provider and reporting setup, and plan an implementation before the mandate.
Book a free 30-minute consultation or talk to us about SAP e-invoicing integration.