How iText by Apryse fuels Wizz Air’s high-volume PDF boarding pass and invoice generation

Wizz Air is a fast-growing low-cost airline operating across Europe with a mission statement of making no frills travel available to everyone at the lowest possible price.

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Wizz Air was established in Hungary in 2003. From their first flight in 2004, to celebrating a remarkable milestone of 200 million passengers carried in 2019, Wizz Air has experienced considerable growth, currently being the 7th largest airline in Europe with a fleet of almost 200 aircraft. With the aim to make no frills travel available to everyone at the lowest possible price, they have now begun to expand their operations beyond Europe.In 2020, Wizz Air was awarded Best Low Cost airline in Europe by AirlineRatings, and were named the Most Sustainable Low-Cost Airline for the third consecutive year at the World Finance Sustainability Awards 2023.

In 2015, to better serve their growing customer base and expansion plans, Wizz Air was looking for a robust and scalable solution for the generation of PDF boarding pass and customer invoices. Their requirements were driven by the following needs:

To handle the large volume of passengers, Wizz Air needed a solution capable of generating boarding pass PDF documents swiftly and efficiently. The process had to ensure quick delivery of boarding passes to passengers while minimizing the risk of delays or inaccuracies. In addition, they required a PDF invoice to be generated and sent out whenever a passenger purchased a ticket.

With millions of passengers flying annually, Wizz Air required a solution that could reliably manage the high-volume boarding pass and invoice generation demands. The chosen system had to be capable of maintaining consistent performance and quality, even under peak load conditions.

To align with their branding and legal requirements, Wizz Air needed the ability to customize the appearance and content of their boarding passes and invoices. This included incorporating branding elements such as logos, fonts, colors, and dynamically generated passenger information.

In addition, Wizz Air’s Head of Engineering and Architecture, Zoltan Homoki, told us they required a PDF solution that could be easily integrated with their existing NET-based microservices architecture systems, and a custom plugin written in the X++ language for Microsoft Dynamics.

The iText PDF library is available for Java and .NET (C#) and has a well-deserved reputation for speed, standards compliance, and stability. Developers appreciate its unique combination of power and ease of use, with high-level API abstractions for document creation, font handling, tables and structured content, and more. Our latest version of the iText Core library, version 8, supports the latest PDF specifications and features, and the iText Suite includes a range of add-ons to provide extra functionality. One of the most popular is pdfHTML, which enables creation of PDF from HTML or XML templates, with wide CSS support for customizable styling.

The .NET versions of the core iText PDF library and add-on for HTML conversion are directly integrated into Wizz Air’s backend Microsoft Dynamics ERP solution and systems responsible for generating boarding passes and invoices. Branded HTML templates for boarding passes and invoices were created with dynamic placeholders, which represent passenger-specific data such as name, flight details, seat number, and payment information.

When a passenger completes their booking through the Wizz Air website or mobile app, the relevant booking and passenger details are collected by the system. The system takes the HTML templates and fills in the dynamic placeholders with the passenger-specific data collected during the booking process. After populating the HTML templates with data, the system uses iText to convert the rendered HTML into PDF format for invoices. In addition, data is sent to a separate microservice for boarding pass generation hosted using a Platform as a Service (PaaS) component of Microsoft Azure.

The generated PDF boarding passes and invoices are stored in the system, with invoices automatically emailed once the purchase is completed. In addition, passengers can either view the PDF boarding pass through the Wizz Air website, on their mobile app, or download the PDF to print as required.

We asked Zoltan Homoki to break down by each use case the amount of PDFs iText generates. He told us “I believe we generate around 60 million documents a year. About one third of the documents are customer invoices, while the other two thirds are boarding passes.”  With that scale of generation, have there ever been any problems? “No, we’ve never needed to do any kind of maintenance to our iText implementation, and its performance has been excellent.”

Wizz Air contracted out their implementation of PDF generation capabilities to an external software development company, who evaluated the available options for PDF libraries. They quickly determined iText’s feature set and performance made it the best choice, and so went ahead with implementation in 2015. However, the contractor didn’t purchase a commercial license, meaning that through no fault of their own, Wizz Air’s implementation of iText was subject to the terms of the AGPLv3 license.

Unlike most PDF SDKs, iText is distributed by Apryse under a dual license model. The iText Core library is available as Free and Open-Source Software (FOSS), meaning everyone has access to its full functionality at no cost, providing they follow the terms of the copyleft AGPLv3 license and make their source code available. At the same time, we also offer commercial licensing for users who wish to develop in a closed-source environment and protect their intellectual property, while receiving professional support and maintenance. In addition, they get access to free updates and the opportunity to influence our roadmap.

This business model has been extremely successful, since the revenue from commercial licensing enables us to fund the continuous development of iText, adding support for the latest features our users need. In turn, the open-source community benefits from full access to our PDF library’s features, driving the wider adoption of our innovative technology and capabilities.

Since the AGPLv3 terms meant Wizz Air could be obliged to release the source code of their application, Apryse worked with them to swiftly arrange commercial licensing along with a professional support and maintenance contract. This meant Wizz Air could continue to protect their IP and move forward with their plans for future growth without issue.

If you have any questions about our licensing terms, or would like advice regarding AGPLv3 compliance, please feel free to reach out to us. We will be happy to assist you and ensure your iText usage is fully compliant.

Like many other airlines who use iText to generate PDF boarding passes, Wizz Air is very happy with how iText performs. As Joel told us, “At Wizz Air, we're looking to make sure that every piece of what we do from a digital perspective, every component, every building block is up to the task - not just for today, but also when we think about how to build the future, That’s why we chose iText back in 2015, why we still use iText, and why we intend to continue using it.”

The PDF generation system built using iText has grown with Wizz Air since its implementation. It continues to perform admirably with no issues to date; even with Wizz Air currently generating around 60 million documents per year, a figure that is growing 20% year on year. Looking to the future, it seems only the sky is the limit for iText and Wizz Air.