Senior Backend Engineer - Fraud Detection Squad

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.

We believe three things matter for every role at Lemonade: drive to push through challenges, efficiency that keeps standards high while moving fast, and adaptability that lets you pivot with data and AI insights. These aren't buzzwords, they're how we actually work.

Our AI-first approach isn't just a tagline either. We're building the future of insurance with AI at the center, and we need people who are genuinely excited to learn and grow alongside these tools.

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)

• Ready to work in an office environment most days of the 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