At Belsimpel, we develop everything in-house.

From the website to the warehouse system, from our CRM system to the spin-offs of Belsimpel.

At Belsimpel, we build everything ourselves. Why do we do that? Because then we are not dependent on external parties and we can implement all the smart ideas we come up with ourselves in the systems we use. And, because it's much more fun to develop! This means that no bridge is too far for us and we can always set the course together with our own smart and fanatical colleagues. The dot on the horizon? That is clear: conquering the mobile world.

View all development vacancies here!

Special onboarding for internationals

Get a 50-hour Dutch course for your skill level - To all non-Dutch speaking colleagues, we offer a language course from the University of Groningen at a level that suits you. At development, we communicate with each other in English, but it can still be nice to learn the Dutch language at our expense.

Work remotely 2 weeks per year extra - We understand that you also want to see your friends and family abroad from time to time. That's why you can work 2 weeks a year in your home country on top of your natural leave.

Tips and help to make your move easier - We will help you with moving tips, permits, visa and explanation about how living in The Netherlands works. This will make your stay in the Netherlands even more enjoyable!

Our stack

.... and don't forget Gitlab, Docker, Typescript and Redis. We use various tools including Jetbrains, Slack, Ubuntu/Windows and vscode. Which tools you use exactly depends on the team you will be working in.

What are we building?

  1. The most advanced telecom webshop of the Netherlands (Belsimpel) and Europe (Gomibo): A fully multi-language platform with the most powerful comparator in the Mobile World. It tames more than 17 price combinations and it can filter on literally anything.
  2. Alice - Our own CRM system which all our customers and colleagues use.
  3. ABS - our own AB-testing platform.
  4. Our own warehousing system that can handle more than a million stock movements per year.
  5. Verifai - an SDK for ID verification for iOS, Android and web.
  6. Tulip Assist - the insurance platform we founded and built ourselves.
  7. Instore software - that's what our shops run on
  8. The Belsimpel and Gomibo app for Android and iOS

And much more. We see ourselves mainly as a software company. If you read the list above, you'll understand why working at Belsimpel is very different from running an online shop ;-) All our software is built with a SaaS mindset where we are users ourselves.

What can you expect from us as an employer?

How do we develop software?

Within all Belsimpel teams you work with like-minded, smart colleagues, so you can continuously learn from each other and get energy from working together. Which team you'll join? We determine that together and it is never fixed for the future. It may well be that you are involved in more than one team at the same time, or that you will eventually move to another team. We do not work with fixed job profiles, but we make sure you get a job that really suits you.

Each team works on its own part of the software. These can be customer-oriented components, but also our warehouse system or our own HR system. You develop, optimise and implement new features. We develop all the systems we work on ourselves, so that we can respond effectively to complex and challenging changes in the market. We also use the systems ourselves, but we build them as independently functioning software that is also interesting for other companies. So, although we are also a web shop, we see ourselves as a software company. So our scope is much broader than you might think.

Belsimpel = 555 phones × 473 contracts × 65 bundles = plenty of choice

And that is why we build everything ourselves.

Build with us!

Meet some of our developers

Our team consists of a mix of smart, studying, recently graduated, and very experienced developers who have been with us for years. Most of our colleagues have done a technical study and have made their hobby into their job at Belsimpel.

Are you joining our team? We love new colleagues! Your positive, critical view and spirit will keep us sharp so we can become even better.



The moment Belsimpel had outgrown Jeroen and Jeroen's student room, I became a developer at That was also the moment that the decision was made to manage the code in-house. I knew Jeroen from university and the interview consisted of a cup of coffee, after which I started working in the development 'department'. It started with creating and maintaining the first website, but the projects and tasks grew along with the company. Today, we are also responsible for the software for the warehouse, customer service, connection desk, financial department, and more! The most enjoyable are projects such as the stock and warehouse system: these are projects that we have created, implemented, and later expanded ourselves. Here you can clearly see that value is added to the company! Besides my work at, I sometimes spend time at home doing geeky projects. From software projects to learn new languages to automating parts of my house, useful or not. The hobby sometimes gives us good ideas that we can apply at and vice versa I can apply the pool table skills I learn at in the pub :)


Front-end Developer

I'm Ruben Langius, front-end developer at Belsimpel. I've been working at Belsimpel for 3 years now. It started as a part-time job next to my Artificial Intelligence study, and now I have been working fulltime for over a year. Besides being behind a computer a lot, I also like to be on the water. Sailing, surfing, wakeboarding, I like it all, as long as I don't have to swim. In my job, I develop all the pages that Belsimpel's customers have to deal with, together with my colleagues. The special thing about my job is that we build a website that is not only used by millions of visitors but also by hundreds of colleagues. From back office pages to a new feature on our product comparison pages, we do it all. At the end of 2020, we made the decision to convert our website to a new modern architecture in which we use React to build our website from standardised components. This is something we are still working on today, and I have been involved in it from the beginning. It is very nice to see the results of this new architecture now, and to be able to validate and possibly revise the choices that were made during development.


Front-end Developer

I am Niels, Front-end Developer at In my function, I ensure that customers can navigate the site as smoothly as possible and that the most important information is communicated to them in a clear manner. I do this, among other things, by optimising the site for display on different screen resolutions. I am also responsible for the emails you receive during the ordering process and the automatically generated PDFs, such as contracts and invoices. In 2013 I finished my studies Brand & Design Management and after that I started looking for interesting job opportunities. On the site of I saw the vacancy for Front-end Developer, and after a successful job interview I started working there. Since I started working at, I have done many different projects, but the most fun and impressive project is the transition to the responsive website. In a few months time we rebuilt the entire front of, where everything had to work properly on phones, tablets, laptops, and desktops. In my spare time I also like to be creative, sometimes with my own sites, but also with photography, drawing, and writing. Besides that, I love series and films, and I listen to a lot of music. The latter also at the office, by the way. Just put on your headphones and go.


Back-end Developer

Hi, I'm Marc, back-end developer at Belsimpel. I'm part of our operational development team. We mainly deal with our in-house developed back office, called Alice. In particular, I work a lot on the warehousing-related code which has to do with stock, order picking and packing, and things like the purchase of products. I also work a lot within the financial parts of our system, which have to do with invoicing or processing purchase discounts, for example. I joined Belsimpel in mid-2018 via a former Computing Science student who already worked here. The first contact was through him, a few days later I could drop by for coffee with Jeroen and a week later I was already at work. The fast-track approach and informal atmosphere really appealed to me then and it still does to this day. The great thing about Belsimpel is that you are a full member of the team from day one. This means that the adjustments to the codebase have a direct impact on systems that many colleagues use and that are of direct benefit to customers. That is great fun and sometimes also a bit nerve-racking. In my spare time I try to do sports regularly, indoor football and cycling (if the weather is nice). I also enjoy playing board games and chess in small groups. Besides that, I am fairly busy with politics in the evenings, but gaming on a free evening is certainly not unpleasant either. I like to make nice long trips and sometimes organise trips for groups of friends, skiing holidays for example. I get a lot of energy from bringing people together and making them happy. A bit like what we do at Belsimpel!

How do we work?

This is how we work together

Is this really for you? View all vacancies

17 million unique combinations of phones, subscriptions and bundles

That does not fit into a Magento or Microsoft solution :)

Who are we looking for?

There are some things that are important to us, for example, that you are smart and positive. Have you just graduated or are you still studying? Then we have lots of projects for you to develop step by step and always enough experienced colleagues to give you the right guidance. Even if you are just starting out, you will be given a lot of responsibility, because we believe that this is how you learn fastest. For developers with a lot of experience, we also have the most challenging projects. The question is not whether we can excite you with cool projects, but more whether you can handle it.

Sufficient challenge & guidance

As a new colleague, you will always have your own projects and a permanent supervisor. This way, you can focus and know that there is always someone you can ask. We also offer various internal training courses to develop your professional skills.

A pleasant working atmosphere where you can be yourself

The development team consists of more than 12 nationalities and a diversity of characters. At Belsimpel, there is plenty of room to do your own thing in the way you like it. Having lunch together? Fun? Prefer to be alone, fine! If you like to socialise in the form of a game night or a drink, we facilitate this on a regular basis. This way you can get to know your own team better as well as people from other teams. And here too: if you prefer not to, that's fine too!

The right stuff

We love it when your computer is fast. So you get a desktop with 3 screens, CPU: Ryzen 2600X, GPU: GTX 1050, RAM: 32GB. Also at home. Some colleagues work on MacBooks because of the nature of their work.

Will you go above and beyond with us?

Check out all the development vacancies here!