Lemonade

Senior Backend Engineer - Fraud Detection Squad

Lemonade Remote Today
engineering

Join our cross-functional fraud detection squad where you'll build systems that protect millions of customers while keeping the good ones flowing seamlessly through our platform.

In this role you'll:

  • Build fraud detection systems using microservices in Typescript (NestJS) and Ruby on Rails, running over Kubernetes to catch bad actors while keeping legitimate customers happy

  • Leverage our autonomous tools to manage development flow—from environment setup to production deployment—so you spend time solving fraud, not fighting infrastructure

  • Collaborate with data scientists, product managers, and fraud analysts in a self-sufficient squad to hit aggressive fraud prevention OKRs

  • Own your domain's code quality, performance, and scalability as fraudsters get smarter and transaction volumes explode

  • Design systems that make split-second decisions on claims and applications, balancing security with customer experience

  • Coach and mentor other engineers while staying ahead of evolving fraud patterns and attack vectors

  • Partner with our AI/ML teams to implement and optimize machine learning models that detect fraud in real-time

What you'll need:

  • 6+ years as a backend engineer, ideally with experience in fraud detection, risk management, or high-stakes decision systems

  • BSc in Computer Science, Mathematics, or equivalent experience

  • Passionate about technology and the cat-and-mouse game of fraud prevention

  • Broad knowledge of modern backend frameworks, tools, and architecture—especially real-time processing and decision engines

  • Experience with high-scale, production-grade projects where uptime and accuracy are non-negotiable

  • Past contributions to open source projects (bonus points for security or fraud-related work)

  • Ability to work in an office environment a minimum of 3 days a week

  • Enthusiasm about learning and adapting to the exciting world of AI—a commitment to exploring this field is a fundamental part of our culture

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