Lead Engineer — Application Security

Overview

In this Lead Engineer role within Klarna’s Secure Development team you help design and deliver secure software. You’ll influence architecture decisions, model threats, and drive security improvements across engineering teams. You’ll combine upstream security work with hands-on assessments, including code reviews and penetration testing, plus build tooling that makes secure practices easy to adopt. This is an opportunity to shape how Klarna ships resilient products at scale. You’ll work in a security-focused culture that values pragmatic, impact-driven engineering.

Responsabilità Perform threat modeling for new architectures and designs

Review architecture and design decisions to harden applications and services

Drive security improvements with engineering teams

Build and enhance security tooling, automation, and processes

Conduct security assessments including code reviews and penetration testing

Contribute to Klarna's internal engineering security community

Requisiti fondamentali Experience with security assessments (code reviews, penetration testing)

Proficiency in at least one language: JavaScript (NodeJS), Python, Go, Erlang, Java, or Scala

Broad knowledge across web/mobile/network security, OS hardening, cryptography, and cloud computing; expert in at least one

Working proficiency in English

Strong communication skills to explain security tradeoffs to non-security engineers

Pragmatic problem solving

Cross-functional collaboration

Clear communication of security tradeoffs

Threat modeling

Architecture and design reviews

Security tooling and automation