Dateio - Master API design

Master API design

Client intro

Dateio is a Czech fintech startup running its own API product based on payment data—TapiX. This app is offered to financial institutions in Europe and also the Middle East as a complementary product. It provides information on locations where bank customers have purchased goods or services, including details like addresses or logos.

Skills used
  • user persona analysis
  • information structure analysis
  • UX & structure design
  • tech writing
  • API review

Our goal was to turn the TapiX developer portal into a product that could be sold and build it up from scratch based on reviewed Swagger documentation. During the process, we put emphasis on user-centricity and comprehensible step-by-step guides.

We were looking for external input on how to design a developer portal well. DX Heroes helped us improve the overall onboarding experience from start to finish with focus on product usability.

Ivan Dovica
COO, Dateio

Initially, the challenge was to focus on the target persona and to effectively communicate the ins and outs of TapiX. Later on, we were challenged by the amount of technical writing needed to fully explain different use cases while still meeting the client's expectations concerning budget and quality.


At the beginning, we identified the key target user personas the portal would be built for—a technical product manager and a developer. Afterwards, we analyzed the way TapiX works and then determined the role and value of every single API endpoint, which later proved very useful during the tech writing stage. On top of that, our UX team designed a custom bottom-up user interface, including an interactive sandbox.


We prepared a bespoke solution to increase customer conversion and to provide a holistic insight into the solution for newly acquired—as well as existing—customers. Our main focus was on easily understandable guides backed by well-designed APIs and seamless user experience.

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