Become our new Senior Back-End JavaScript Engineer

Merelbeke, Belgium

Senior Back-End JavaScript Engineer

We’re a SaaS scale-up based in Merelbeke and New York City. We’ve been recently selected by Deloitte as one of the fastest-growing tech companies in Belgium.

Whenever you watch a video ad on the Web, there’s a good chance that our technology is in there. We specialize in optimizing the delivery of those ads: we plug in tech from our customers, such as fraud detection or visual overlays, and while we’re at it, we also make the ad load faster.

We’re a group of individuals that shoots for the stars. Everyone at Zentrick contributes to the success of our cutting-edge technology. In return, we provide a friendly atmosphere where our international team can learn fast and exchange knowledge. We like each other, so at least once a month we do something fun together!

About You

As part of our senior team of back-end engineers, you’ll own our web services that handle hundreds of thousands to millions of requests per minute. Currently, those are written in Node.js, but we’ve also started to experiment with running directly on v8 or using alternative languages such as Go.

In ad tech, performance is key. It definitely helps if you know how to profile your code, because shaving a few milliseconds off a request can allow us to turn off dozens of servers and have a measurable impact on revenue, not to mention global warming.

That said, as you’ll be involved in building the service from the ground up, you should have a good understanding of software architecture and design patterns. We’ve found that a Master’s degree helps there, but it’s not a strong requirement.

We’re committed to delivering high quality through agile development. If you’ve already done pair programming, code reviews, and daily stand-ups, you’ll probably fit right in.

We’re looking for a team player who isn’t afraid to express their opinion. It’s through the continuous exchange of ideas and even the occasional constructive discussion that we usually reach the best decisions for our product, our customers, and our team.

Finally, we pride ourselves on our excellent relationship with our customer’s engineering team. Maintaining that relationship is a big part of the job, through frequent conversations and by going the extra mile to truly understand the customer’s needs.


We know we’re asking a lot, so we’re also giving a lot back. More precisely:

  • a competitive wage;
  • a generous vacation schedule;
  • flexible working hours;
  • half a day per week for personal development;
  • a personalized growth plan;
  • group insurance;
  • hospitalization insurance;
  • meal vouchers;
  • eco vouchers;
  • compensation for public transportation and biking;
  • extras tailored to your preference.


Sounds like you? Don’t wait too long, send your resume to

Apply now