Senior Backend Engineer Utrecht

Vacancy: Senior Backend Engineer Utrecht

• Do you get energy from modeling complex financial systems correctly, where metering, pricing and money math have to be exactly right at scale?
• Do you want to build the monetization rails behind the AI economy, the infrastructure that lets modern software, APIs and AI agents actually get paid?
• Would you like to work with conceptually strong engineers, including people who built payments infrastructure at scale, on greenfield products in a scale-up with proven product-market fit?
• And do you say yes to a salary up to €100.000 plus stock options and a 5% bonus, with real influence on the product?

Then read on!

Your Employer: FinTech Scale-up Building the Financial Layer for Usage-Based and AI-Native Software

This Utrecht-based scale-up builds the financial backbone for a clear market shift. As AI, automation and real-time usage become the norm, the old "fixed license per month" model no longer matches how software is actually consumed. Companies need financial systems that adapt to real usage, handle genuine complexity, and stay correct to the cent. What makes this interesting for an engineer is the depth of the problem: metering, pricing, credits, wallets and revenue recognition are a deceptively hard modeling domain where the hard part was never the metering, it was getting the abstractions right. Every event you process is money, so correctness is not a nice-to-have, it is the product.

The timing is ideal. Product-market fit has been proven, major customers are live, and the platform is preparing for international expansion. At the same time this is still an environment where engineers shape foundational decisions. New SDKs, greenfield initiatives and the core choices around scalability, data and cloud architecture are being made right now, which means your work compounds rather than disappearing into a backlog.

The culture is technically driven, entrepreneurial and content-focused. You work alongside engineers who care about getting the concept right, not just shipping a framework, and diverse backgrounds and perspectives are actively valued because they lead to sharper discussions and a stronger product. Knowledge sharing is part of how the team works, autonomy is high, and the shared goal is to build something that will still matter ten years from now.

Your Role: Senior Backend Engineer Utrecht

As a Senior Backend Engineer Utrecht, you play a key role in the evolution of the platform. You work with Kotlin, Ktor, Kafka, Kubernetes, GCP, BigQuery and PostgreSQL to design and build scalable backend services, real-time metering and data pipelines, and the APIs and billing primitives that sit at the heart of the product.

You are involved across the entire product lifecycle, from designing new services to building, testing and running them in production. This is genuine you build it you run it. The technical challenge is less about volume and more about precision: modeling pricing and billing logic that has to stay correct under growth, under concurrency, and under the messy reality of how customers actually use software. You make the foundational calls on data and cloud architecture and you own the consequences.

You collaborate closely with the product team to ship new monetization capabilities, including the infrastructure that lets AI products and agents be priced and billed per real usage. For an engineer who likes hard, conceptual problems with real-world stakes, there are few cleaner examples than money that has to be right.

Growth Opportunities

Because the platform is still being shaped, there is room to grow into a foundational technical role: owning architecture, setting standards around correctness and reliability, and going deep as a domain expert in financial infrastructure. As the company scales internationally, the engineers who built the core are the ones best positioned to lead its next layers.

What's Required?

• At least 5 years of experience in backend development
• Strong with Kotlin and/or Java and frameworks like Ktor or Spring Boot
• A conceptual, modeling-first mindset: you care about getting abstractions and correctness right
• Experience with event-driven architectures is a major plus
• Experience with cloud platforms (preferably GCP) and containerization (Kubernetes)
• Knowledge of databases such as PostgreSQL or BigQuery
• A completed technical BSc or MSc, plus strong communication skills
• Available to work on-site in Utrecht 4 days per week + Stand By service

What's Offered?

• Salary between €80.000 and €100.000 gross per year, depending on experience
• Stock options in a scale-up with serious momentum (could be your pension one day)
• 5% annual bonus for pension
• Travel allowance
• MacBook of your choice
• Lunch provided at the office
• Beautiful office right next to Utrecht Central Station
• Work alongside very strong engineers

Do you want to build the financial infrastructure behind usage-based and AI-native software, while growing your own career within a world-class engineering team?