The introduction of the mandatory National e-Invoice System (KSeF) is revolutionizing the workflow of financial documents in Poland. Businesses are therefore faced with a challenge: how can they integrate with KSeF quickly, securely, and as seamlessly as possible, without wasting valuable resources and IT team time? Ksefapi.pl is here to help—a comprehensive and modern integration tool that solves all the most common issues related to direct integration with KSeF.
Integration with KSeF without the headache: ready-made libraries, REST API and usage examples
Integration with the official KSeF API provided by the Ministry of Finance requires knowledge of:
- generating XML documents compliant with the current XSD schema,
- signing documents with private keys using asymmetric cryptography,
- support for X.509 certificates (PEM, DER, PFX),
- performing authorization using JWT or XMLDSIG signatures.
All of this requires understanding highly complex technical processes. The lack of step-by-step documentation in official materials means that development teams must figure out every aspect of integration on their own. Using ksefapi.pl significantly simplifies this process, as the solution:
- provides ready-made PHP, .NET and Java libraries,
- provides a simple, standardized REST API,
- offers detailed documentation along with sequence diagrams to best illustrate business processes, starting from generating invoices in line with the applicable schema and ending with sending invoices to KSeF.
This allows your IT team to focus on handling business invoices, rather than struggling with XML or public keys.
Technical support that really works – interact with a human, not a bot
One of the biggest challenges with self-integration with KSeF is the lack of real technical support. Official contact channels are limited, and response times are unpredictable, or often nonexistent. Meanwhile, ksefapi.pl relies on real people, thanks to which:
- you receive email and telephone support directly from the technical team,
- each message contains a phone number to a specific person – you can call and discuss the problem without intermediaries,
- updates, corrections and adaptations to changes in KSeF are implemented on an ongoing basis as part of the purchased plan.
As a result, you not only save time, but also gain a sense of security and business continuity, which will be especially important when e-invoicing becomes mandatory.
Who are we and what have we achieved?
Experience matters – meet the team behind ksefapi.pl
Behind the success of every solid SaaS solution is a competent team. In the case of ksefapi.pl, we're talking about over 20 years of experience in IT projects, including:
- designing and implementing API interfaces (REST, SOAP, GraphQL),
- integration of ERP/CRM systems with public registers (GUS, Ministry of Finance, KRS and VIES),
- automation of accounting and e-commerce processes.
This team also develops:
- nip24.pl – a platform for automatic NIP, REGON and VAT checking,
- viesapi.eu – a service for mass verification of EU contractors in the VIES database.
This experience in public API integration translates into the highest level of refinement of the ksefapi.pl system, both in terms of technology and organization.
Tailored licensing offer – you only pay for what you need
One of the greatest advantages of ksefapi.pl is its flexible licensing model, which can be tailored to any business, from a micro-enterprise to a large enterprise. In practice, we offer:
- a model based on the number of inquiries (for smaller companies or occasional invoicing),
- monthly or annual subscription (for companies with a large number of documents and the need for 24/7 integration),
- licenses for the number of invoices issued or the number of clients served.
What's more, updates resulting from KSeF API changes are included in the price. There are no hidden costs, unforeseen invoices, or "compatibility" surcharges.
What characterizes our product licensing method?
Standalone integration with KSeF vs. ksefapi.pl – cost and risk comparison
When deciding on integration with KSeF, it is worth asking yourself a few questions, namely:
- How many hours will it take my team to analyze the official documentation and implement it?
- What will be the cost of errors and delays if documents are not correctly sent to KSeF?
- who will update the system when the Ministry of Finance changes the XSD structure or the authorization method?
Do-it-yourself integration is a huge amount of work, and the actual costs (time + man-hours + maintenance) often significantly exceed the price of a ready-made solution like ksefapi.pl. It's also important to note that by using it:
- you pay for a working and proven solution,
- you don't worry about legislative changes,
- you are provided with support and updates as part of your subscription.
This is a solution that was created by entrepreneurs for entrepreneurs who not only value their time, but also count costs.
Programming languages and technologies – what does ksefapi.pl support?
One of the most common questions IT departments ask is: will our technologies be compatible with ksefapi.pl? The answer is yes. Ksefapi.pl offers:
- REST API that can be implemented in any language (e.g. Python, Node.js, Go, Ruby, Java, C#, Scala),
- ready-made client libraries for PHP, JAVA, .NET,
- detailed documentation extended with sequence diagrams illustrating key business processes.
All libraries contain ready-made classes, objects, and functions that shorten the integration process to an absolute minimum. And if something is missing, the ksefapi.pl team responds quickly to user needs.
In summary, ksefapi.pl was created for entrepreneurs, developers, and managers who want to focus on their business, not on analyzing incomprehensible XML schemas, integrating with digital signatures, or laboriously deciphering technical documentation scattered across government websites. Thanks to ready-made libraries, a transparent REST API, intuitive documentation, and real technical support, ksefapi.pl transforms something potentially difficult into something predictable, fast, and professional. Add to this flexible licensing models, the developers' extensive experience, and active product development, and you have a tool that truly deserves your attention.
