Lead Engineer — Application Security

You'll perform threat modeling and architecture and design reviews, helping teams design hard-to-break applications and services.

You'll take an active role in architectural decisions, working directly with engineering teams to drive security improvements.

You'll build and improve Klarna's security tooling, automation, and processes on an ongoing basis.

You'll perform security assessments of Klarna services, including code reviews and penetration testing.

You'll contribute to Klarna's internal engineering security community.

You take a pragmatic approach to solving security issues, weighing effort against effect rather than chasing theoretical risk.

You break down complex systems, spot where they're likely to fail, and land on fixes that work in practice.

You've written and reviewed code in at least one of: JavaScript (NodeJS), Python, Go, Erlang, Java, or Scala.

You're proficient across several of web application security, mobile application security, network security, operating system internals and hardening, applied cryptography, and cloud computing — and you're an expert in at least one of them.

You have working proficiency in English.

Experience with BugBounty programs or CTF competitions.

Communication skills that hold up when explaining security tradeoffs to engineers who don't work in security day to day.

This position works cross-functionally across Klarna's engineering division, not within a single product team.

We welcome candidates from non-traditional or self-taught security backgrounds — what matters is what you've built, broken, or fixed, not how you got there.

Please include a CV in English. Concrete beats comprehensive — what you built, what it did, what it cost. Curious to learn more about Klarna and what it's like to work here? Explore our career site !