Senior Backend Engineer (Customer Auth) in London

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. Last year alone, the businesses on our platform generated £7.2bn for the UK economy.

Location & Compensation: London (Hybrid) – 2 days in the office. Competitive salary and benefits.

The Customer Auth team builds the foundational security and identity platforms that power Funding Circle’s transition to a modern, distributed architecture. The team owns the critical systems responsible for securing customer access and managing complex business relationships for all product teams.

Responsibilities:

• Build, run and maintain authentication and authorisation systems.
• Take product scope, design the technical solution and deliver it.
• Work closely with Product and other engineering teams that use your systems.
• Engage in green‑field development while also digging into older codebases as needed.
• Work in a complex problem domain that is implemented with simple software systems.
• Collaborate – encourage pairing and work together instead of siloed work.
• Teach – generously share time and expertise to help stakeholders and fellow engineers find solutions.

Qualifications:

• Experienced in Python.
• Senior level – able to lead and influence architectural decisions while mentoring and up‑skilling junior engineers.
• Strong fundamental programming skills with experience in distributed systems.
• Familiar with developing on 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.
• Acts as a technical bridge and mentor, training “builders” across the company from basic AI usage to sophisticated system creation.

Why join us?

We back you to build an incredible career. 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.

Benefits:

• Flexibility: A benefit allowance you can tailor to your own life and family.
• Health: Private medical and dental, health assessments, and access to a digital GP.
• Wealth: Life assurance, share schemes and financial coaching.
• Development: A dedicated annual learning allowance.
• Lifestyle: Electric car and cycle‑to‑work schemes, plus season ticket loans.
• Award‑winning parental leave policies.

Ready to join a mission that matters? We’d love to chat!