How to Prepare for KSeF – Step by Step

From 2026, all businesses in Poland will have to use KSeF - the National e-Invoice System (from January 2027 for the smallest firms with monthly sales up to 10,000 PLN and invoices under 450 PLN). This means: 

• no more PDF invoices sent by email 
• no more issuing invoices “locally” 

For an invoice to be valid, it must go through the Ministry of Finance's system. 

Sounds serious? Because it is. 

But switching to such a system doesn’t have to be scary or difficult. Quite the opposite – the Ministry isn’t doing this to make life harder. The goal is to make everything work more efficiently. 

This article isn’t about what KSeF is (you can read more about that in this article). 

Here we’ll focus on how you and your business should prepare for this change, so you don’t wake up in January with a major problem. 

Here are 5 things you should consider doing now – without waiting until the last minute: 

 

1. Check if Your Invoicing System Supports KSeF 

Do you use a tool to issue invoices? Maybe something dedicated to invoicing or an ERP system? 

You should check if your current software is (or will be) compatible with KSeF. To pass through the Ministry’s system, an invoice must be in the correct XML format and include all required fields. A well-integrated system will automatically detect whether an invoice is ready for sending. In some tools, external integration may be necessary. 

How to check it: 

1. Log into your invoicing tool or ERP system. 
2. Look through the documentation or contact your provider – ask about KSeF integration. 
3. Make sure the system generates XML files that meet the Ministry’s requirements. 
4. Try exporting a sample invoice and see if it passes validation in the KSeF test environment. 
   
   
   

 

2. Set Up a Digital Signature or Company Seal 

Every invoice in KSeF must be sent by an authorized user, and permissions are assigned based on a digital signature or seal: 

1. Individuals (e.g., sole traders, employees issuing invoices) can authorize using a qualified signature or Trusted Profile (Profil Zaufany). 
2. Companies (legal entities) can additionally use an electronic company seal – in this case, employees don’t have to sign each invoice manually. 

Don’t have a signature yet? You can get one online – e.g., via Profil Zaufany. 

How to do it: 

1. Check if you already have a qualified signature or Trusted Profile. 
2. If not, apply online through a provider or via Profil Zaufany. 
3. Ensure all team members responsible for invoicing also have the necessary authorization. 

 

3. Assign the Right Permissions 

Having a signature isn’t enough. You also need to assign specific people (and systems) the right to issue invoices on behalf of your company in KSeF. 

You can do this via the e-Tax Office. 

You can also assign a technical token – a sort of “pass” for your ERP system. 

Step-by-step: 

1. Log into the e-Tax Office. 
2. Select the option to assign permissions in KSeF. 
3. Add people or systems as authorized invoice issuers. 
4. Generate a technical token if your ERP system requires it. 

💡 Tip: If multiple people issue invoices in your company, consider using a company-wide digital seal instead of individual signatures – it simplifies the process. 

 

4. Test Sending Invoices 

Good news!  The Ministry of Finance will make a test environment available on September 30th, where you'll be able to check if your invoice passes validation and if the system reads it properly. 

Test it yourself and try out how you'll be sending invoices in the future. It's better to fix any issues now when you have time, rather than starting the new year stressed out because you can't send invoices :) 

You’ll find the test environment here: 👉 KSeF test environment 

💡 Tip: When testing, use real data but replace the tax ID (NIP) with the test NIP: 5250001009 – this way you won’t send an actual invoice to a client. 

 

5. Train Your Team 

KSeF isn’t just for accountants. If your invoices are issued by sales reps, customer service, or even production teams – they need to understand the new process too. 

It’s worth preparing a short how-to guide or even a simple tutorial video on how the new invoicing works. 

Remember! Most errors come from user mistakes. 

 

What's Next? 

Whether you like it or not, from February the new KSeF system will be mandatory in Poland. It might seem intimidating at first (it’s new, after all), but now you know how to prepare your business for the change – so you’re all set! :) 

Whether you're using a basic invoicing tool or a full ERP system – the key is to ensure it’s ready for KSeF integration. If your current solution can’t handle it, maybe it’s a good time to consider switching to a system that supports both KSeF and your other business needs in one place. 

Odoo is one such system. KSeF integration already works, and you also get sales, inventory, accounting, and other modules all in one platform. Once implemented, this integration supports your whole business and grows with you. 

We at Solvti will be ready when that moment comes — we're already working on a KSeF module today that allows you to send e-invoices to the Ministry in an incredibly simple way. Want to learn more about it? Book a short online meeting.