Stripe Integration with iFirma: A Complete Guide for 2026

Introduction — Why connect Stripe with iFirma?

Stripe is a global payment gateway that enables accepting card payments from around the world. However, the platform does not offer Polish VAT invoice support or integration with the National e-Invoice System (KSeF). This means every transaction must be separately invoiced in an accounting system and from 2026 submitted to KSeF.

iFirma is a Polish accounting and invoicing application designed for micro-businesses and sole proprietorships. The system is renowned for its extensive list of integrations — it can be connected with Allegro and popular e-commerce platforms (Shoper, WooCommerce, PrestaShop), with fiscal devices and bank accounts (payment export and single-code approval). Thanks to integration with the GUS database, entering a NIP number automatically fills in the remaining contractor data. iFirma is developing its KSeF module — invoices will be sent to the government system automatically upon saving in the programme, without the need to log into external portals, and users can monitor document statuses.

With mandatory e-invoicing coming in February and April 2026, connecting Stripe with iFirma becomes a necessity. Instead of manually re-entering data, you can use the Striptu integrator, which automates the entire process — from a Stripe payment, through invoice issuance in iFirma, to sending it to KSeF.

What is KSeF? A brief overview of the regulations

The National e-Invoice System (KSeF) is a government platform for issuing, transmitting, receiving and storing structured invoices. The system was created to digitise the invoicing process and reduce errors. According to the schedule:

- 1 February 2026 — KSeF becomes mandatory for businesses that achieved sales (including tax) above 200 million PLN in 2024.
- 1 April 2026 — the obligation extends to other companies.
- Businesses with revenue up to 10,000 PLN per month can wait until 1 January 2027.

KSeF requires that every sales invoice be submitted to the government system within a specified time after issuance, making accounting automation crucial. iFirma is preparing for full integration — the system will enable receiving and sending invoices to KSeF directly from the application and monitoring document statuses.

Why Stripe cannot issue a VAT invoice or send it to KSeF

Stripe focuses on payment processing and does not generate Polish VAT invoices — the confirmations it issues (receipts) do not contain a NIP number, the correct VAT rate or numbering required by Polish regulations. Furthermore, the platform does not provide an interface for direct submission of e-invoices in XML format to KSeF. In practice, this means that without an additional tool, selling through Stripe requires manually issuing an invoice in a Polish system, downloading it in FA(3) format and sending it to KSeF — which is inefficient and error-prone at high transaction volumes.

Why choose iFirma?

iFirma is a comprehensive invoicing and accounting tool that stands out with several features important for online sellers:

- Broad integration ecosystem — iFirma can be easily connected with Allegro and popular e-commerce platforms such as Shoper, WooCommerce and PrestaShop. This allows you to automatically import orders and issue invoices without switching between systems.

- Bank and fiscal device integration — the system integrates with fiscal devices and enables payment export to banks and single-code approval. This greatly simplifies operations for entrepreneurs using online settlements.

- Automatic contractor data completion — thanks to GUS database integration, simply entering a contractor's NIP number automatically fills in the remaining data (name, address).

- KSeF support — iFirma is preparing a module that will allow invoices to be sent to KSeF directly from the system, with sending triggered automatically when a document is saved. Users will be able to monitor statuses and receive invoices from KSeF, ensuring full regulatory compliance.

Connecting iFirma with Stripe automates the entire process: the system issues a VAT invoice based on transaction data, sends it to KSeF and delivers the PDF to the customer. No transaction will be missed, and you maintain compliance with applicable regulations.

How to integrate Stripe with iFirma using Striptu

Striptu is a Polish SaaS that connects global payment platforms (Stripe, Kajabi, ThriveCart) with Polish accounting software. Thanks to our tool, after every Stripe payment, an invoice is automatically issued in iFirma and then sent to KSeF. Below you will find a step-by-step guide on how to configure the integration.

1. Create a service and connect Stripe

1. Register on Striptu, choose a plan (monthly for 29 PLN or annual for 290 PLN) and create a new service.
2. Connect your Stripe account: generate a Secret API key in the Stripe developer dashboard and enter it in Striptu. Our tool will automatically create a webhook and capture payment notifications.

2. Enable iFirma integration and complete the configuration

1. In the Striptu dashboard, open the created service and go to the Settings tab.
2. In the iFirma tab, enter:
* Username — your iFirma login.
* API Token — the authorisation key obtained from the iFirma dashboard.
3. Click Test connection.

Where to find the API token? Log into iFirma, go to the Modules menu, then select API. In the "Modules and Integrations" window, click the Integrate button and generate a token for the Invoice identifier. Copy the generated key and paste it into the Striptu configuration.

3. Define the income tax rate (flat-rate) and other settings

- If you settle accounts on a flat-rate basis, iFirma requires specifying an income tax rate. In the Striptu dashboard, you can set a default rate that the system will pass to iFirma.

- In the Additional settings section, enable the Automatically send invoice email to customer option — after issuing a document, we can ask iFirma to send the PDF to the email address provided in the Stripe transaction. Make sure email sending is enabled in the iFirma dashboard.

- If you do not use the Tax module in Stripe (it does not pass the net amount), set a default VAT rate in Striptu, e.g. 23%, so the programme calculates net and VAT values on the invoice. For products with different VAT rates or international transactions, consider enabling Stripe Tax and configuring tax rates.

4. Test and launch the integration

After configuring the connections, it is worth running a test payment in Stripe test mode. Check whether the invoice appears in iFirma, whether it contains the correct data (NIP, VAT rate, net/gross amounts) and whether email delivery works. Then switch to production mode and automate the process for real transactions.

Benefits of Stripe → iFirma → KSeF automation

Automatic connection of Stripe, iFirma and KSeF brings many tangible benefits:

- Time savings and elimination of manual work — our integration collects transactions from Stripe and creates invoices in iFirma automatically. Invoices are issued immediately after payment, eliminating the need to re-enter data.

- Compliance with Polish law — by using iFirma with its built-in KSeF module and GUS integration, you can be sure that invoices contain all required fields and will be submitted in the correct format.

- Fewer errors — data from Stripe is automatically transferred to the invoice; our system transmits only the necessary information for a VAT invoice, and you can add a NIP number and order comments as needed. Automation minimises the risk of mistakes.

- Fast document delivery — after issuing an invoice, iFirma can send the PDF via email to the customer and immediately submit the e-invoice to KSeF. The customer receives proof of purchase almost instantly, and you fulfil your tax obligation.

- Status monitoring — iFirma allows monitoring whether invoices have been accepted by KSeF and receiving cost documents from KSeF. You have full control over the document workflow.

- Future-readiness — implementing the integration before mandatory KSeF allows you to test processes and avoid problems during the transition period. The first 10 transactions in Striptu are free, so you can test the solution risk-free.

Summary

KSeF will change how Polish companies issue and send invoices. From 1 February 2026, large enterprises, and from 1 April 2026, other companies will be required to submit sales invoices in structured form. Stripe itself does not offer Polish VAT invoices or KSeF integration, so the only path to compliant accounting is connecting it with a Polish accounting system.

iFirma is the ideal tool for this: it automates invoice issuance, integrates with e-commerce, banks and GUS, and the KSeF module will enable sending and receiving invoices directly from the application.

To fully automate the process, it is worth using Striptu. Configuring the Stripe → iFirma integration takes just a few minutes: simply provide your iFirma login and API token, set your preferences and test the connection. Our system will take care of issuing the VAT invoice, submitting it to KSeF and sending the PDF to the customer — while you gain time to grow your business.