From 2026, Poland is introducing mandatory use of KSeF (Krajowy System e-Faktur), the national electronic invoicing system operated by the Ministry of Finance. This reform fundamentally changes how VAT invoices are issued and validated, replacing traditional PDF and paper invoices with structured electronic invoices in XML format submitted through a central government platform.

KSeF applies not only to Polish companies, but also to foreign businesses that are VAT-registered in Poland and required to issue Polish VAT invoices, particularly for B2B transactions. Currently, mandatory KSeF generally applies to domestic B2B transactions. B2C transactions and certain cross-border supplies may fall outside the mandatory scope, depending on the applicable VAT invoicing rules. For sellers using marketplaces such as Amazon, KSeF compliance is closely linked to platform invoicing rules and operational continuity.

Why KSeF is more than a technical change

Under KSeF, invoices must be issued in a structured XML format and transmitted to the government system for validation. Once approved, the invoice receives a unique KSeF number and becomes the only legally valid original. Invoices issued outside KSeF, where mandatory, may be treated as non-compliant and can affect VAT deductibility and overall tax compliance.

This reform is designed to increase transparency, enable near real-time VAT control, and reduce tax fraud. As invoicing and VAT reporting become tightly integrated, businesses must ensure that their invoicing processes are fully aligned with KSeF requirements.

KSeF mandatory rollout timeline

The obligation to use KSeF will be introduced in phases:

• 1 February 2026 – Large taxpayers with 2024 annual turnover exceeding PLN 200 million
• 1 April 2026 – All other VAT-registered businesses in Poland, including foreign entities
• 1 January 2027 – Micro-entrepreneurs with monthly invoicing not exceeding PLN 10,000

Although KSeF mainly targets B2B transactions, businesses with mixed B2C and B2B sales should prepare early, as invoicing needs may change over time.

What Amazon sellers need to do

According to Amazon’s latest seller communication, its VAT Calculation Service (VCS) is expected to support KSeF-compliant invoicing for Amazon Business sales. However, Amazon can only issue KSeF invoices on behalf of sellers if it has been formally authorised in the KSeF system.

Key points to note:

• From 1 February 2026 – Amazon can issue KSeF invoices only if authorisation is completed
• Between 1 February and 31 March 2026 – Amazon may temporarily issue PDF invoices if authorisation is missing
• From 1 April 2026 – Amazon will stop issuing invoices for unauthorised sellers, who must then issue KSeF-compliant invoices themselves

Before authorising Amazon, sellers must first obtain access to the KSeF system. Our KSeF Amazon Authorisation Service supports clients through this one-off process, typically completed within two to three weeks.

Prepare early to avoid disruption

KSeF will be mandatory and strictly enforced from 2026. Sellers must either authorise Amazon to issue invoices on their behalf or be ready to issue compliant KSeF invoices independently. Early preparation is the most effective way to reduce compliance risk and ensure business continuity as Poland moves into a new era of digital VAT administration.