Stripe Integration with KSeF: A Guide for 2026

What is KSeF and why does it affect businesses using Stripe

The National e-Invoice System (KSeF) is the central platform of the Ministry of Finance for issuing, transmitting and storing structured e-invoices in XML format. From 2026, the system becomes mandatory for entrepreneurs. Large companies (turnover above 200 million PLN) must issue e-invoices from 1 February 2026, and other entrepreneurs from 1 April 2026 — an additional transitional period allows micro-businesses to wait until 1 January 2027.
KSeF requires that every sales invoice be submitted to the government system almost immediately after issuance (transitional provisions allow 24–72 hours for submission).
Entrepreneurs using Stripe — a global payment platform — must therefore take care not only of accepting payments but also of issuing Polish VAT invoices and submitting them to KSeF.

State of KSeF as of 28 January 2026

At the time of writing (28 January 2026), the new version of KSeF is not yet fully available. The Ministry of Finance announced that between 26–31 January 2026, a technical break for KSeF 1.0 is in progress; the system, including the certificates and permissions module, is disabled.
During this break, the ability to verify KSeF 2.0 services in the production environment was made available — you can check authentication, permissions and token generation. However, the full launch will take place on 1 February 2026, when the target KSeF 2.0 version becomes the only available and mandatory system, and the previous version 1.0 ceases to function.
This means that entrepreneurs preparing their invoicing processes for mandatory KSeF currently have limited access to the production environment — tests can be conducted, but production issuance and submission of e-invoices will only be possible after KSeF 2.0 goes live.

Why Stripe does not work with KSeF

Stripe is a global payment platform that enables accepting payments in multiple currencies. However, it does not offer Polish VAT invoice issuance or KSeF integration.
As shown in a Striptu article, Stripe focuses on payment processing, and invoicing and tax settlement matters are left to the seller. Stripe does not know the format of a Polish invoice (NIP number, correct VAT rate, proper numbering), so each sale must be invoiced independently.
The platform does offer the Stripe Tax module for VAT calculation and sends customers transaction confirmations, but these "receipts" do not meet Polish VAT invoice requirements and are certainly not e-invoices in the XML format required by KSeF.
The result? If you sell online courses, e-books or digital services through Stripe, you must issue a VAT invoice yourself and from 2026 submit it to KSeF. Manual invoicing for each transaction is, however, time-consuming and error-prone.

Available accounting software with KSeF integration

Several accounting and invoicing systems on the Polish market have adapted to KSeF and can automatically send invoices to the government system.
A Striptu blog article mentions Fakturownia.pl, wFirma, inFakt and iFirma, among others. Here are their key features:

Accounting software	Key capabilities	Documentation details
Fakturownia.pl	Free KSeF integration; invoices issued in the system can be sent to KSeF with one click.	Configuration requires entering the account name (subdomain) and API token and testing the connection with Fakturownia.pl. You can enable automatic invoice PDF sending to the customer's email and set a default VAT rate.
wFirma	The programme enables automatic sending of sales invoices to KSeF and retrieves the KSeF status/number for each document.	Integration in Striptu requires entering two API tokens (access key and secret key) and testing the connection. You can set a default VAT rate and automatic invoice PDF sending to customers.
inFakt	The programme integrates with KSeF and enables automatic e-invoice submission after providing an authorisation token; it also retrieves the KSeF number.	The Striptu guide requires generating an API token in inFakt settings and granting appropriate permissions for creating and reading invoices. As with other systems, you can set a default VAT rate and automatic email invoice sending.
iFirma	The accounting platform announces full KSeF integration. According to Striptu, integration should be available in early 2026 — the programme will support invoice submission to KSeF, document retrieval and other features (e.g. retrieving contractor data from GUS).	The Striptu guide states that configuration requires providing your iFirma login and an API token generated in the API module; the token is created for the "Invoice" identifier and entered into Striptu settings. More about iFirma integration configuration in the documentation. The system enables setting a default VAT rate, default income tax (for flat-rate) and automatic invoice sending to customers.

Why choose these programmes?
Each of the above systems generates structured XML files compliant with KSeF, enables invoice submission to the government system and handles receipt of return identification numbers. This allows entrepreneurs to focus on selling while e-invoices are sent automatically.

Integrating Stripe with accounting software — how Striptu works

Since Stripe does not offer built-in invoicing or KSeF integration, it is necessary to connect it with a Polish accounting system using an integration platform. Striptu is a Polish SaaS system designed precisely to "stitch" global payment platforms (Stripe, Kajabi, ThriveCart) with local accounting software supporting KSeF.
The process works as follows:

1. You connect Stripe with Striptu — you authorise access to your Stripe account. From that point, Striptu can receive information about new transactions.
2. You connect Striptu with your chosen invoicing programme — you provide the API token from Fakturownia, wFirma, inFakt or iFirma.
3. VAT invoice generation — when a payment appears in Stripe, Striptu creates a sales invoice in the accounting programme. The document contains customer data, amount, VAT rate, numbering and other required fields. This eliminates manual data re-entry.
4. Automatic submission to KSeF — because the accounting programme has an active KSeF integration, the freshly issued invoice is forwarded to the government system. In Fakturownia, submission occurs automatically after saving the document, confirming its official registration.
5. Archiving and status — the invoice receives a KSeF identification number, goes to the archive (stored for 10 years) and remains accessible both in the accounting programme and in KSeF. This lets you fulfil KSeF obligations effortlessly.

Why you should not connect Stripe directly with KSeF

At first glance, it might seem that since both Stripe and KSeF offer APIs, it would suffice to write your own script and send invoices directly to the government system. In practice, however, this approach carries a number of risks:

* Technological complexity — a self-built integration requires generating invoices in XML format compliant with the FA_VAT schema and adapting to constantly changing KSeF specifications. Such integration is complex and expensive to maintain.
* Authentication and security — submitting e-invoices to KSeF requires using a Trusted Profile or certificates and generating tokens. Keys must be stored securely and permissions refreshed.
* Data orchestration and validation — Stripe stores transaction data in its platform-specific format. To send an invoice to KSeF, you need to recalculate amounts (e.g. for foreign currency transactions), add NIP numbers, VAT rates, calculate exchange rates according to the NBP table, generate proper document numbers and ensure invoice uniqueness. Manual processing increases the risk of errors and delays.
* Risk of non-compliance — KSeF verifies e-invoice correctness; errors in XML structure or missing required fields cause document rejection. Your own script will require constant updates to keep up with legal amendments.
* Maintenance cost and lack of support — by building your own solution, you take responsibility for its development and maintenance. In case of failure or changing legal requirements, you must react yourself. For most small businesses and online creators, this is not cost-effective.

Instead of writing your own integrator, it is worth using ready-made solutions (Fakturownia, wFirma, inFakt, iFirma) and connecting them with Stripe via Striptu. This gives you not only peace of mind and regulatory compliance but also access to technical support and system updates.

Benefits of automatic Stripe → KSeF integration

Automated invoice integration has many advantages:
- Time savings — invoices are issued automatically after each payment; no need for manual data entry.
- Compliance with Polish law — using systems prepared for KSeF (Fakturownia, inFakt) guarantees that invoices contain all required fields and are submitted in the correct format.
- Fewer errors — data from Stripe is transferred automatically (including NIP and address), which minimises missed transactions and incorrect invoices.
- Fast delivery — the invoice reaches the customer (PDF email) and KSeF almost immediately after payment. This speeds up the document workflow.
- Future-readiness — early implementation of automation allows learning procedures, catching errors and being ready when KSeF becomes mandatory.

Summary

Mandatory KSeF will change how invoicing works in Poland. Today (28 January 2026), production KSeF 2.0 is still awaiting launch — technical work will continue until 31 January, and the new system goes live on 1 February.
Meanwhile, Stripe — despite handling payments excellently — does not issue Polish invoices and does not integrate with KSeF. Therefore, the only sensible solution is to use Polish invoicing programmes with a KSeF module (Fakturownia, wFirma, inFakt, iFirma) and connect them with Stripe via Striptu.
Ready-made integrations automate the entire path: Stripe payment → invoice issuance in accounting software → submission to KSeF → PDF delivery to customer. This ensures compliance, reduces errors and saves time.

If you want to prepare your business for mandatory e-invoicing, start now — test the integration, generate API tokens in your chosen accounting system and configure Striptu. When KSeF 2.0 launches in February, your processes will be ready, and you can focus on growing your business.