JavaScript Developer

Leuven, Belgium (Europe)



About THEO Technologies

THEO is a deep tech B2B company, on a mission to shape the rapidly evolving online video landscape. The media industry that we have long known is rapidly changing. Media consumption patterns have shifted towards online video. As a company we provide high-impact media solutions for media companies around the world that enables them to offer exceptional video experiences across any device.

With our flagship product THEOplayer, used by tier 1 media companies worldwide, we are a recognised market leader in the video playback domain. The company has been awarded the Streaming Media Reader's Choice Award in the Video Player category for the last 3 years running (2017, 2018, 2019), confirming its game changing role.

THEO was awarded the Fastest Growing Technology Company in the Media and Entertainment Category in the Belgian Deloitte’s Technology Fast 50 Awards in both 2018 and 2019.

Our culture is based on trust, high performance and self-development where we believe in a more organic culture with the right balances and motivations.


Job Description

We are looking for an experienced JavaScript Developer to strengthen the THEOplayer Core team at THEO Technologies.

You help us lift the core of our THEOplayer product to a higher level by improving the software architecture, developing advanced algorithms, optimizing and implementing features and helping your peers improve their coding practices.

You love the challenge of a technically complex product and believe that every technical challenge can be overcome by good architecture, clean code and teamwork.

All our engineers are both specialists in certain domains and generalists in our technology. We are a fast-growing company, which creates many opportunities to constantly evolve and grow in your role.

Duties & Responsibilities

  • Make clever use of technology to tackle performance and cross-platform challenges in TypeScript and HTML5;
  • Be proactive at improving the THEOplayer code base, architecture and functionality;
  • You’re a vibrant part of our team of passionate developers and help juniors to improve their coding practices;
  • Work together with product managers to analyze functional requirements and design, document and implement an appropriate solution;
  • Work together with in-house testers to bring the quality of our solutions to a world-class level;
  • You work in an agile team. This means you should feel comfortable with working in short sprints, pair programming, daily standups, test-driven development, …
  • Occasionally, you work directly with our customers to help them deploy our product in their Android apps and resolve any issues they are facing.

Desired Skills & Experience

  • 3+ years of experience as a JavaScript (TypeScript) software developer;
  • Excellent eye for good code architecture and clean code;
  • Strong knowledge of JavaScript (TypeScript) and its core concepts (prototypal inheritance, event loop, …);
  • A knack for refactoring;
  • You are happy to mentor junior software developers and help them improve their coding practices;
  • Familiar with core web technologies like DOM manipulation, XHR, …
  • Experience with streaming media is an advantage;
  • Experience in mobile environments (Android, Swift) is a plus;
  • You’re a team player that knows when to work together and when to fly solo;
  • Tons of energy, passion, humor and enthusiasm;
  • Loving the challenges and atmosphere of a young and fast-growing company.

What We Offer

  • A versatile full-time job in the animated city Leuven.
  • A competitive salary with plenty of extra benefits.
  • The opportunity to work for an exciting start-up conquering the world.
  • A place to learn and get in touch with the cutting edge of online video.
  • The company itself is doing exceptionally well. For career-motivated people, there will be upward mobility.
  • A stimulating working environment.
  • Nice and passionate colleagues.
  • Flexible hours.
  • Regular and fun team activities.

Does this sound interesting to you?

Please send your resume and cover letter to We look forward to hearing from you.

Looking for another opportunity at THEO Technologies?