Luciana Terceiro

UX & User Research

PagSeguro Card readers

2013 – 2016

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Since 2013, the company has developed different card readers for small businesses. The first device was a simple magstripe card reader that could be plugged into the smartphone’s audio plug. The following devices were either card readers that could be paired to a smartphone or stand-alone card readers.


It was our first experience planning and designing a product interface for platforms other than computers or mobile phones. When the project started, we weren’t aware of possible technical limitations or requirement details.

It is relevant to mention that almost half of the Brazilian population didn’t have a bank account then, and the regular bank communication was quite unclear to the public.


Create an effortless experience for a potential public that wasn’t very tech-savvy. The goal was to design a self-explanatory interface for the card reader with a strict limitation on the number of characters.

Work process

1. User research

Our first step was a series of interviews to understand small sellers’ needs and struggles. We focused on researching card readers’ users and non-users to understand their problems and challenges regarding the devices and how they usually run the business.

2. Prototype and usability tests

In the next step, we started to design prototypes and execute usability tests. We decided to start with paper prototypes because installing test interfaces in the card readers wasn’t a simple process. Also, it was an unusual test with a device people were unfamiliar with. By using paper prototypes, we believed people would feel more comfortable testing and giving us their feedback.

After the paper prototyping phase, we reproduced identical prototypes on Axure and executed the same testing process. With these second batches of usability interviews, we could refine and improve the communication of the interface. We also found other product problems related not exclusively to the interface that was communicated to other teams, such as the lack of accessibility for blind people.

3. Usability tests on pilot devices

When the card readers were ready with the designed interface, we performed more tests with sellers, considering other aspects such as Internet connection and communication speed.

User research with card readers’ users and non-users.
Paper prototyping and card sorting.
Usability tests with the card readers.
Internal tests.

My role

Team lead – assisting and guiding the team on planning the different research methods and orienting the prototyping stages.


The PagSeguro card readers are one of the most sold machines in the Brazilian market. The company was a pioneer in giving these solutions to small businesses. By developing the card readers, we learned a lot about the user experience of other platforms and devices than the usual ones like computers or mobile phones.

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