Working on the HSL project

Our employees work on various customer projects, often partly at the customers’ premises. That’s why we don’t always know precisely what everyone is working on at the time. Thus, it’s interesting to hear in more detail how our consults’ projects are going and what they include – of course within the limits of our customers’ data projection.

This time we interviewed Antton, who is working in our HSL customer project. Let’s hear what he had to say:


How did you end up in the HSL project?

It was a pleasant surprise, to be honest! I started working at Poplatek and got into the project right away. It was nice to start with a project like this, knowing that the work we do has so many end-users.


What kind of team do you have and what is your project all about?

In our team, there’re me and Sami from Poplatek, and we have mainly done payment-related software development. We implemented the adding of a payment card and card payments to HSL app. In practice, we designed and programmed a totally new payment API to our payment service. The work mainly consisted of Java programming to the backend system, but also AWS Lambda coding with Python.


Two different kind of APIs were implemented into the backend: open ones, which are called by the card form and ones requiring authentication, which are called by the backend system of the HSL app. APIs were executed so that the form and the backend system call for AWS Lambda, which handles the request and forwards it to the system if everything is in order. It has been interesting to reason how to execute public APIs, so that their misuse is not possible.


Besides the development of the backend system, we also developed a new card form, in order to answer better for the needs of HSL and other customers. The form was executed without third-party libraries, because PCI requires that the vulnerabilities of libraries are monitored, and all the content in the form is served from the same address. The most reasonable solution was to carry out the payment form with Vanilla JavaScript for operational reasons. The development process was really interesting as I hadn’t before been a part of a project where the transaction certainty and the handling of sensitive payment card data need to be considered.


Have you encountered new technologies in the project? Would you like to learn something new?

In my current project, I use Java and Node.js. The latter was a new acquaintance and I learned to use it at work. I like coding in both languages, but JavaScript intrigues me a bit more, as it’s possible to code both frontend and backend with it. I would also like to learn to manage AWS cloud services better. Not so much related to work, C# and game programming would also interest me.


You’re quite often at our own office. How much time do you spend at HSL?

Last fall (2018), I spent a lot of time at HSL’s premises, usually about four days a week. Now I have been a part of Poplatek’s other customer projects so I have spent more time at our own office. The pipe repair work at HSL has also influenced the situation.


What is the most pleasant way of working for you?

I don’t really have a preference. I like our own premises at Poplatek, so I enjoy being here. Usually I go to the gym in the morning, so I have the energy to sit in front of a computer for the rest of the day. Flexible work hours have also helped as I don’t have to get up from bed during the small hours.


What are your plans for summer holidays?

I have a lot of plans, but not anything too special. I’ll probably spend most of my time stand up paddle boarding and playing beach volley at our cottage. At the end of my vacation, I might go fishing for crabs. Furthermore, I’ll take my nephew to a funfair, Tivoli Seiterä (I got the tickets from my colleague – Thanks Hanna!).


Throw us a tip for the rest of the summer!

All of you hungry people near Mikkeli, I strongly recommend visiting Angela Kebab and giving their Calzone a try! Works for sure – especially for a bigger hunger.


Would you like to be part of interesting projects? Apply and join our competent and easygoing Poplatekcrew. Check our open positions here!

Antton Lappalainen

Antton Lappalainen

Full Stack Developer

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