Lead Kotlin Backend Engineer

• Do you want your engineering decisions to have a direct impact on revenue, user behaviour and platform performance?
• Do you enjoy working on real-time, high-traffic systems where latency, stability and release quality truly matter?
• Are you a senior or lead backend engineer who leads naturally through technical excellence, not hierarchy or titles?
• And do you want the freedom of fully remote work while still being part of a strong, mature engineering team?

Then this role is built for you.

Your employer: a large-scale digital marketplace with real-time global impact

You will join a well-established European digital platform operating at significant scale, used daily by users across many countries. The product sits directly in the core of commercial activity: everything that happens in the user journey has a measurable effect on revenue.

The organisation combines the stability of a mature platform with the speed of a product-driven tech company. Engineering teams are trusted, pragmatic and focused on building systems that work reliably under pressure. There is little bureaucracy, no excessive process and a strong emphasis on ownership and technical responsibility.

With a full remote first setup, only having to go to the office 2 days per month!

The platform processes large volumes of real-time interactions and is continuously evolving to improve performance, scalability and user experience.

Your role: Senior/Lead Kotlin Backend Engineer Amsterdam (lead by example)

In your role as lead backend engineer you lead a tech savvy team, where systems that must handle high load, real-time updates and frequent releases without compromising stability.

As this team touches scaling, performance it is important that you can lead by example. You influence decisions through expertise, code quality and clear reasoning.

The team currently consists of experienced backend and frontend engineers and is already running smoothly. You will be the fifth engineer in a balanced, well-functioning team. This is not a rescue mission and not a greenfield rebuild. It is about raising the bar.

This team sits directly on the revenue stream. Improvements in performance, reliability or UX immediately translate into higher conversion and better results.

Your teamis responsible for everything users see and interact with (performance & revenue critical):

• searching and discovering assets
• browsing and viewing auctions
• bidding in real time
• integrations with web and mobile clients

The team currently consists of experienced backend and frontend engineers and is already running smoothly. You will be the fifth engineer in a balanced, well-functioning team. This is not a rescue mission and not a greenfield rebuild. It is about raising the bar.

Typical topics include:

• designing and improving GraphQL and REST APIs
• building and optimising real-time flows using WebSockets
• improving performance, throughput and latency
• ensuring release stability across web and mobile clients
• contributing to architectural discussions and trade-offs

You take ownership end-to-end: from design to implementation, from performance analysis to production behaviour. You review code, challenge assumptions and help the team make better technical decisions.

This role is ideal for a strong senior engineer who:

• already acts as a technical reference point, or
• wants to grow into a light, pragmatic lead role without people management

• 7+ years of professional JVM backend engineering experience
• Demonstrated experience helping other software engineers and be better at their job
• Professional experience with functional programming
• Experience within Event Driven Architecture, Cloud native and microservices environment
• Strong experience building and operating backend systems at scale
• Solid understanding of performance, concurrency and failure modes
• Experience with API design (REST and/or GraphQL)
• Experience working on user-facing, high-traffic systems
• Pragmatic mindset: improving systems incrementally rather than chasing hype
• Comfortable working autonomously in a mature engineering team
• Strong communication skills and technical clarity
• Experience as tech lead is a big plus
• Experience with Kotlin or Scala is a plus

• Between €85.000 and 100.000 per year + 8% bonus
• Fully remote working from within the Netherlands
• Only 2 office days per month (Amsterdam)
• 25 vacation days
• Modern hardware and tooling
• Stable, mature platform with real engineering challenges
• A role where technical excellence directly impacts business results