Implementing KSeF: Checklist, Timeline

Wondering how to implement the National e-Invoicing System (KSeF) in your company?
The GoNextStage analytics team has prepared a checklist of 7 essential steps to help you roll out the National e-Invoicing System in full compliance with regulations — and with maximum efficiency.

Core Principles and Requirements of KSeF

The National e-Invoicing System aims to standardize the invoicing process in Poland by introducing a mandatory electronic workflow for invoices in XML format.

KSeF Timeline

Feburary 2026

mandatory for large enterprises (annual turnover exceeding PLN 200 million)

April 2026

mandatory for all remaining VAT taxpayers, including sole proprietors and SMEs

January 2027

mandatory for the smallest businesses (sales documented by invoices of up to PLN 10,000 per month)

How to Prepare for KSeF? Timeline

By the end of 2025

1 Verify Your Systems’ Compliance with KSeF

Review your financial accounting system (ERP) and digital invoice workflow system. In many cases, integrating with a BPM (Business Process Management) system allows you to capture more data, which in the long run enables better financial reporting for your organization.

2 Apply for an Invoice Issuer Certificate

Starting November, you can apply to the Ministry for an invoice issuer certificate. Do it as early as possible!

3 Choose How You’ll Handle e-Invoices

You can choose between:

the Ministry of Finance portal,
your ERP system,
or an invoice workflow application integrated with KSeF via the GoNextStage KSeF Connector.

Get familiar with the FA(3) logical structure — the mandatory schema for structured invoices. Each field in your invoice must be properly tagged according to this schema.
The GoNextStage analytics team makes this easy: during the KSeF Connector implementation, you’ll receive a tool for mapping all fields together and later, seamlessly convert them into XML format.

4 Check If You Handle Invoice Attachments

If you receive invoices with attachments, make sure your system supports such documents. If you send invoices with attachments, you must obtain permission from the Tax Office by February to process these documents through KSeF.

5 Need Support?

Leverage the experience of the GoNextStage team, who have optimized business processes for companies like mBank Hipoteczny, GCity, and Echo Investment. Together, you’ll implement an invoice workflow management system fully compliant with KSeF requirements.

By February 2026

1 Assign KSeF permissions to the people responsible for managing your company’s invoice workflow.

2 Test your invoice handling processes with KSeF: issue test invoices through the National e-Invoicing System and verify that your systems correctly retrieve and archive documents.

3 Train your team on the new procedures and the implemented system.