Junior Front End Developer

Who We Are

We are a Sofia based company and care about the city we live in. At Theoremus, we have a common vision that we want to share and live in cleaner, healthier, happier and better cities overall, and we know that to live this dream today means we have to combine skills, reason and passion in a bold, new way.

We’ve gained expertise and are currently focused on two main areas:

• Mobility аnalytics & ticketing – We pride ourselves in developing Sofia’s public transportation ticketing system, and especially its online components, such as the QR tickets and the debit card payments. Furthermore, on top of that, we have developed its advanced analytics sub-system, which measures the behavioural patterns of public transit passengers, and aims to optimise for a frictionless experience. Our goal is to continuously enhance user experience and encourage people to limit the use of private vehicles, and thus improve urban mobility, traffic and air quality in the cities where your friends and family live.
• Smart waste management – Our know-how in the waste management sector has been disseminated into multiple projects throughout Bulgaria and Spain. We have developed big IoT systems consisting of thousands of sensors attached to trucks and containers. The aim of these systems is to deploy data science methods in order to optimise the circular economy lifecycle and make waste taxation fairer.

What we seek for:

• Understanding of front-end architectures and application design principles
• Knowledge of HTML5, CSS3 and TypeScript
• Familiarity with SPA frameworks / libraries – (preferably React)
• Ability to tell stories through complex data 🙂
• A high degree of autonomy
• Interest in modern event-driven microservice architectures, based on stream processing, machine learning, and big data technologies
• Curiosity. Passion. Desire to make an impact. Strong expertise is important – no doubt – but it can be learnt and developed on the job.
• That’s it. A solid background and a splash of enthusiasm make the perfect match!

What you’ll learn:

• Mobility and waste management are the two biggest sustainability areas of a city (they take the largest percentage of a budget in a city).
• You’ll learn a lot about these two domains and will understand how technology can be deployed for good.
• Independently own the entire front end development process from mocks, prototype, UX testing, development and integration with the backend components.
• How modern data-driven systems which underline the data science process are developed, monitored and maintained over time.

What you’ll do:

• Design, develop and maintain awesome new features and components
• Contribute to weekly UI/UX meetings
• Take initiative and suggest problems as well as solutions – any idea could potentially lead to a cool feature
• Communicate, collaborate, share knowledge and ideas

What We Offer

• Competitive salary and real career growth in an innovative company.
• Additional health insurance and Multisport card to keep you healthy.
• Public transport card – because we believe in sustainable mobility.
• 25 days of annual paid leave – because we know rest is important.
• Fridays that end at 2 PM – because balance matters.
• A team that values learning, creativity, and having fun together.
• An amazing office in Sofia’s city center with a 360-degree panoramic view and a summer terrace for coffee, networking, and cake (we love cake).

A mission that matters – your work will improve city life for thousands of people.

What We Believe In
We don’t just write code – we build systems that make cities smarter. Part of our values:

• Services over monoliths – Keep things modular and scalable.
• Prototyping before development – Test before committing.
• Science over technology – Data-driven decisions over hype.
• Trust over processes – You get ownership, not micromanagement.
• People and sustainability first – Tech should serve people, not profits alone.

AI as a tool to eliminate repetitive coding tasks – so our team can focus on solving complex, meaningful problems that drive innovation.

That’s the short version. We know we’re not alone on this journey.

How to Apply?

If this sounds like the kind of place where you’d love to grow, let’s meet 🙂

Send us your CV and GitHub (or a project you’re proud of).

If you don’t meet all requirements but you’re excited about what we do, apply anyway – we care about potential, not just experience!