Lead Kotlin Backend Engineer Amsterdam

Vacancy: Lead Kotlin Backend Engineer Amsterdam

• Do you enjoy designing and owning backend systems where correctness, consistency and domain modelling matter?
• Do you want to work in a Kotlin-first environment that takes functional programming seriously?
• Are you a lead backend engineer who prefers clarity, strong abstractions and explicit trade-offs over accidental complexity?
• And do you want to work remote-first while shaping a core platform used across multiple countries and millions of users?

Then this role is built for you.

Your employer: a large-scale digital marketplace with deep operational complexity

You will join a well-established European digital platform operating at significant scale, used daily by customers across many regions. Behind the scenes sits a complex operational backbone that supports everything the business does.

Engineering here is deliberate. The organisation favours Kotlin-first backend development, strong domain modelling and functional principles to keep complexity manageable as the platform grows. Decisions are made for long-term maintainability. They combine product-driven development with real operational responsibility.

Engineering teams are trusted to make decisions, improve systems incrementally and take ownership over critical domains. There is little hierarchy, minimal bureaucracyand a strong focus on pragmatism and long-term maintainability.

The company operates remote-first, with only two office days per month in Amsterdam.

Your team: Platform / Back-office (business-critical systems)
This team forms the operational heart of the platform. These systems are absolutely critical to the business.

The team is responsible for:

• complex business workflows
• integrations with systems such as ERP, CRM and internal tooling
• API-heavy services with many dependencies
• correctness, data consistency and long-term stability

The landscape consists of roughly 8–10 core backend services with deep domain logic and many integrations. These systems are mission-critical: when they fail, the business feels it immediately.

The team is currently being strengthened with permanent senior engineers to reduce dependency on externals and build a stable internal core.

Your role: Lead Kotlin Backend Engineer Amsterdam

In this role as Lead Kotlin Backend Engineer Amsterdam, you take ownership over a complex backend domain. You are not expected to rewrite everything. Instead, you bring structure, calm and technical judgement.

You work hands-on in Kotlin-based backend services and help evolve the platform incrementally. You influence architecture through experience, not dogma. You understand trade-offs and know when stability matters more than elegance.

You lead by example:

writing clear, maintainable backend code

improving service boundaries and data models

guiding architectural decisions pragmatically

helping other engineers reason about complexity

bringing overview where systems have grown organically

This is a role for someone who enjoys owning systems over time and making them better step by step. Part of your role is growing your team by replacing external backender engineers with internal

What is required

• 7+ years of professional backend engineering experience on the JVM
• Strong experience with Kotlin, Java or Scala with a passion for FP
• Experience working on complex, business-critical backend systems
• Strong understanding of data consistency, integrations and failure modes
• Experience designing and maintaining APIs
• Experience with event-driven and distributed systems
• Experience working in cloud-native environments
• Ability to bring structure to complex domains
• Strong communication skills and technical clarity
• Experience mentoring or guiding other engineers is a big plus
• Nice to have
• Deep Kotlin production experience
• Experience with Arrow, Ktor or similar FP-oriented tooling
• Experience with platform evolution or legacy modernisation

What is offered

• Salary 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
• High ownership role within a core platform team
• The opportunity to shape long-term backend stability and quality

If you enjoy complex domains, long-term responsibility and making backend systems calmer, clearer and more reliable over time, this is where you will thrive.