Electronic invoicing · Peppol · mandatory from Jan 1, 2027
E-invoicing and connecting your system to Peppol
From January 1, 2027, VAT payers in Slovakia must issue domestic invoices to businesses as structured e-invoices and send them through the Peppol network. We connect your ERP, e-shop, CRM or custom software to e-invoicing so invoices go out and come in automatically — no retyping and no replacing the system you know.
- mandatory e-invoicing for VAT payers
- 1. 1. 2027
- e-invoice format under EN 16931
- XML
- projects since 2012
- 600+
- average from 62 Google reviews
- 4,9★
In short
Everything that matters in one place
- What is changing
- From January 1, 2027, mandatory electronic invoicing applies in Slovakia (Act No. 385/2025 Coll., an amendment to the VAT Act). Domestic invoices between businesses must be in a structured XML format under the EN 16931 standard and are delivered through the Peppol network. A PDF sent by email or paper will no longer be enough.
- What we do
- We connect ERPs, e-shops, CRMs and custom software to send and receive e-invoices, build invoicing modules and apps, automate incoming invoice processing and also deliver e-invoicing in our own Proon CRM and ERP.
- Who it is for
- For companies that invoice from their own system, e-shop or older software, and for software companies that want to offer e-invoicing in their product under their own brand. We work for companies in Slovakia, the Czech Republic and Austria.
- How
- Through a certified digital postman (a Peppol access point) that delivers the invoice to the customer and at the same time reports the legally required data to the tax authority. We build the integration via API directly in your system.
- Price
- Individual, based on your system and invoice volume. After a free consultation, you get a proposed solution and a price within 48 hours.
- Technologies
- Laravel, Symfony, REST API, UBL 2.1 and EN 16931, integration with AI and MCP. We build our own systems in-house, so we are not limited by an off-the-shelf plugin.
- Proof
- We develop our own Proon CRM and ERP with invoicing and inventory, B2B portals and back office systems. Since 2012 we have completed more than 600 projects and hold a 4.9 rating from 62 Google reviews.
Why deal with it now
Is an invoice in PDF enough?
For domestic invoices between businesses, not from January 1, 2027. An e-invoice is a data file that the customer's system reads on its own. So your system must be able to create and receive the invoice — which also affects customer master data, numbering sequences and approval of incoming invoices.
Check my systemYou invoice from your own software
An older ERP, e-shop or custom system won't create an e-invoice on its own. We add XML export and a Peppol connection.
You must be able to receive e-invoices too
The obligation to receive e-invoices covers a wider range of companies than issuing them — including some non-VAT payers.
Errors in customer data
A wrong company ID, tax ID or Peppol ID means an undelivered invoice. We review and complete master data before launch.
Manually retyping invoices
E-invoicing is a chance to get rid of retyping. We match incoming invoices with orders and send them for approval automatically.
What we solve
E-invoicing from A to Z
From connecting your existing system and automatically processing incoming invoices to a custom invoicing app.
ERP · e-shop · CRM
Connecting your system
We teach your current system to issue an e-invoice in XML under EN 16931 and send it via Peppol directly from the interface you already use. You see delivery statuses right on the invoice.
incoming invoices
Receiving and processing
Incoming e-invoices are automatically loaded into the system, matched with an order or delivery note and sent for approval. Your accountant gets ready-to-use data.
Proon CRM and ERP
E-invoices in Proon
If you are looking for a new system, our Proon CRM and ERP brings quotes, orders, inventory and invoicing together in one place — with e-invoicing and no extra tools.
custom development
Invoicing app
When you need your own rules — recurring invoices, advance payments, multiple companies or re-invoicing — we build an invoicing module or a web and mobile app.
for software companies
E-invoicing under your brand
Do you develop your own software? We build e-invoicing into it so your customers use it as part of your product, under your brand.
preparation
Audit and transition
We map where and how you invoice today, check customer data and prepare a transition plan so you are ready before the deadline.
Not sure which of these you need?
Tell us what you invoice from today. Within 48 hours you get a proposed solution and a price tag.
What you get
E-invoicing that runs on its own
The goal is not just to comply with the law, but to have invoices flow through the system without manual work — from issuing and delivery to bookkeeping.
I want e-invoicing in my systemSending via Peppol
The invoice goes out directly from the system through a certified digital postman.
Receiving e-invoices
Incoming invoices load automatically, with no downloading of email attachments.
EN 16931 format
XML in UBL 2.1 format with all mandatory data and validation before sending.
Delivery statuses
For every invoice you see whether it was delivered, accepted or rejected.
Customer Peppol IDs
Verifying recipients in the Peppol network and adding the data to your company directory.
Matching and approval
An incoming invoice is matched with the order and sent to the responsible person for approval.
Accounting integration
Data export to your accounting software or directly to your accountant.
Archive
Issued and received e-invoices stored and searchable in one place.
Technologies
Technologically no ceiling
We build websites, apps and business systems in-house on the Laravel and Symfony frameworks. That is why we don't connect e-invoicing through an off-the-shelf add-on, but directly in your system's code — with all the exceptions your invoicing has. We can also make invoicing data available to AI assistants via an MCP server, so you can ask about invoice status directly in Claude or ChatGPT.
Peppol
E-invoice delivery
EN 16931
XML in UBL 2.1 format
REST API
System integration
Proon
Our CRM and ERP
Laravel · Symfony
Custom development
AI · MCP
Invoices in your AI assistant
Custom software
Systems we have built
Proon. Business
Our own CRM and ERP with quotes, inventory and invoicing
Verdeline
Custom B2B ordering portal
Heart of Slovakia
Back office system for order management
MIBA SK
Website, B2B zone and back office for partners
MR. Digital — Client Zone
Client invoices, projects and requests in one app
Proon. Business — mobile app
CRM, quotes and invoices on your phone
Little time remains until January 1, 2027
Be ready before the deadline
The first consultation is free and non-binding. We look at the system you invoice from and what needs to be added, and within 48 hours you get a proposed solution and a price.
Overview
Who e-invoicing applies to and from when
| From Jan 1, 2027 | From Jul 1, 2030 | |
|---|---|---|
| Transactions | Domestic invoices between businesses (B2B) and to the public sector (B2G) | Cross-border transactions within the EU as well (ViDA package) |
| Issued by | VAT payers established in Slovakia | Extended to non-established persons |
| Received by | Companies and entrepreneurs, including some non-VAT payers | Under ViDA rules |
| Format | Structured XML under EN 16931 (UBL 2.1 or CII) | European standard EN 16931 |
| Delivery | Peppol network via a digital postman, with data also reported to the tax authority | Digital reporting within the EU |
| Invoices to consumers (B2C) | The obligation does not apply | — |
We cover it in more detail in the article E-invoicing from 2027.
Process
How the switch to e-invoicing works
We start with an audit, not with coding. First we find out where and how you invoice today — only then do we integrate.
01
Invoicing audit
We map the systems you invoice from, invoice types and the flow of incoming invoices.
02
Solution proposal
We recommend connecting your existing system, Proon or a custom app — whichever makes sense.
03
Master data
We check and complete company IDs, tax IDs and Peppol IDs of customers and suppliers.
04
Peppol integration
We build sending and receiving of e-invoices via a digital postman directly in your system.
05
Testing
We test real invoices, delivery statuses and exceptions before going live.
06
Launch and support
We train your team, monitor the first weeks of operation and handle legislative changes.
Related services
Invoicing is part of the whole system
FAQ
Frequently asked questions
Didn't find your answer? Write to info@mrdigital.sk or call +421 949 612 022.
Ask usWhen does e-invoicing become mandatory in Slovakia?
From January 1, 2027. The obligation is introduced by Act No. 385/2025 Coll., which amended the VAT Act. It covers domestic invoices between businesses and invoices to the public sector. Cross-border transactions within the EU will be added under the European ViDA package from July 1, 2030.
Do I need to deal with e-invoicing if I'm not a VAT payer?
VAT payers must issue e-invoices. The obligation to receive e-invoices, however, is broader and also covers some companies that are not VAT payers. If you receive invoices from suppliers, it is wise to be ready to receive them.
Isn't it enough to send a PDF invoice by email?
Not for domestic invoices between businesses from 2027. An e-invoice must be a structured XML file under the European standard EN 16931 that the customer's system reads automatically. A PDF, a scan or a Word document does not meet this requirement.
What are Peppol and a digital postman?
Peppol is an international network for the secure exchange of electronic documents between businesses. A digital postman is a certified provider (a Peppol access point) that delivers the invoice to the customer's postman and at the same time reports the legally required data to the tax authority. We take care of the connection through a digital postman for you.
Do I have to change my invoicing system because of e-invoicing?
Usually not. We can connect your current ERP, e-shop or custom software to e-invoicing via API, so your team keeps working in the system it knows. If the system can't handle the new requirements or you plan to replace it anyway, we recommend our Proon CRM and ERP or a custom app.
Can you connect an e-shop to e-invoicing?
Yes. For orders from businesses, the e-invoice is issued and sent automatically after payment or dispatch. Invoices to consumers (B2C) are not subject to the e-invoicing obligation and can stay as they are today. More about e-shops on the e-commerce solutions page.
Can you process incoming invoices automatically?
Yes. Since an e-invoice contains structured data, incoming invoices can be loaded automatically, matched with an order or delivery note, sent for approval and prepared for accounting. No more retyping or searching for invoices in emails.
Can I offer e-invoicing in my own software?
Yes. If you develop software for your customers, we build e-invoicing into it so they use it as part of your product under your brand — including sending, receiving and delivery statuses.
How much does an e-invoicing integration cost?
The price depends on the system you invoice from, the number of invoices and whether you also want automatic processing of incoming invoices. After a free consultation, we send you a proposed solution and a price within 48 hours.
When is the best time to start?
As soon as possible. The integration and especially checking customer data take time and testing on real invoices. Companies that start at the last minute risk not being able to invoice in January.
Do you also work for companies in the Czech Republic and Austria?
Yes. We work for companies in Slovakia, the Czech Republic and Austria. The Peppol network is international, so we can also prepare a solution for companies that invoice abroad or to the public sector in other countries.
Google review · Banská Bystrica
“A marketing agency that has stood by us since our very beginning. They built our website, create all our social media content and run our marketing campaigns.”
Google review · Bratislava
“We've worked together on two projects, which shows how satisfied we were with the first one. A professional and expert approach.”
Google review · Bratislava
“They built us a comprehensive e-learning platform and also helped refine our ideas and the overall project strategy.”
Google review · Banská Bystrica
“From the very start to the completion of the project, they took care of every detail and built us a beautiful website.”
Google review · Banská Bystrica
“After experience with other suppliers, I can only recommend them. Their expertise and approach won me over. Thank you for the collaboration!”