Senior Engineer (Customer Auth)

We’re on a mission to back the UK’s small businesses like no one else 🚀 Small businesses are the backbone of the economy, and we’re here to help them win. We’ve built a platform that uses clever data to get them the funding they need in minutes, not weeks. At Funding Circle, we have the restless energy of a fintech start-up with the stability of a public company. It’s a unique mix that gives Circlers the autonomy to take ownership and the scale to make an impact that truly counts. We’re a high-performing team that chooses to lift each other up. We challenge, we champion, and we have each other’s backs - because we know that when we stand together, we move faster and build better. The impact is real: Last year alone, the businesses on our platform generated £7.2bn for the UK economy 📈 Come and join a mission that matters! [ Read our Impact Report ] | [ See our Trustpilot ] The role ⚡ 📍 London (Hybrid) | 🤝 2 days in the office | 💰 Competitive Salary + Benefits We are looking for a Senior Engineer in our Customer Auth team. The Customer Auth team builds the foundational security and identity platforms that power Funding Circle's transition to a modern, distributed architecture. We own the critical systems responsible for securing customer access and managing complex business relationships for all product teams. • You will build, run and maintain authentication and authorisation systems • You will take a product scope, design the technical solution and deliver it • You will work closely with Product and with other engineering teams who use your systems • You love to build new things - much of the team's work is greenfield - but also don’t shy away from digging into older codebases • You love to work in a complex problem domain that is implemented with simple software systems. • You are a collaborator - you encourage pairing and believe that working together is smarter than working in a silo • You are a teacher - generous with your time and expertise to teach stakeholders and our fellow engineers how to answer their own questions Hear from our Software Engineer, Judith , about what its like to be part of our Product Engineering team! What we’re looking for 🌱 We value deep expertise, but a growth mindset and good energy are what really make our team click. We’re a group that chooses to lift each other up and think smart every day. • Experienced in Python • A senior who is able to lead and influence architectural decisions whilst mentoring and up-skilling more junior engineers • A strong fundamental programmer with experience in distributed systems Familiar with developing with AWS, Kubernetes, Kafka and serverless • Knowledgeable of Agile, TDD and CI/CD • Excellent communication skills, both written and spoken • Engages actively and collaboratively with team members and stakeholders • Able to architect custom AI solutions and smart automated systems that are safe, maintainable, and aligned with our long-term mission • Act as a technical bridge and mentor, training “builders" across the company to move from basic AI usage to sophisticated system creation. We’re building a place where everyone truly feels they belong. Even if your past experience doesn't align perfectly with every requirement, we'd still love to hear from you. Why join us? 💜 We back you to build an incredible career and by joining us, you'll be part of one of The Sunday Times Best Companies to Work For 2026 ! As a flexible-first employer, we use a "best of both" approach. We’ll see you in our London office to collaborate – with barista coffee and subsidised Just Eat lunches on us! Our Circler Proposition focuses on five areas: • Flexibility: We provide a benefit allowance you can tailor to your own life and family. • Health: This includes private medical and dental, health assessments, and access to a digital GP. • Wealth: We offer life assurance, share schemes, and financial coaching. • Development: You get a dedicated annual learning allowance to help you level up. • Lifestyle: We have electric car and cycle-to-work schemes, plus season ticket loans. We also have award-winning parental leave policies. We're here to support you through the big life moments, from fertility treatments to new additions to the family. Ready to join a mission that matters? We’d love to chat!