Senior Back End Engineer (DE Tech) in London

Requirements

• Proven track record in designing and building backend systems using Python, ideally with Django but open to other web frameworks such as FastAPI, Flask, or Ninja.
• Experience working with relational databases, ideally PostgreSQL but open to MySQL or similar, with an understanding of performance and maintainability considerations.
• Experience working on systems that support complex workflows, where data correctness and clear system behaviour matter.
• A track record of taking work from an initial problem through to delivery, including shaping solutions, making trade-offs, and iterating based on how systems are used.
• A drive to continually improve existing systems, not just building new ones, including simplifying and addressing long-standing pain points.
• Desirable: Knowing how to scale systems: Familiarity with working on internal tools or platforms used by large operational teams.
• Desirable: Full-stack flexibility: Contributing to front-end codebases, particularly with React or TypeScript.
• Desirable: Modern deployment experience: Working with CI/CD pipelines or deployment workflows.
• Desirable: A data-driven mindset: Using data or metrics to assess whether changes have had the intended effect.

What the job involves

We’re looking for a Senior Back End Engineer to build the systems that power iwoca’s German business. You’ll join one of the engineering teams focused on our German market, a cross-functional group that builds the proprietary tools (like our CRM) that our German operations staff use every day. You’ll own high-impact projects from the ground up, using your technical experience to improve how we serve small businesses while also helping to level up the wider engineering team. You’ll work on the systems that both internal and external teams rely on to serve customers. You’ll take engineering work from an initial problem through to delivery and see the outcome in daily use.

You’ll design and build back-end services that support core operational workflows, including customer communication, underwriting, and collections. Simplify workflows: You’ll decide when and what to automate, translating operational needs into reliable code that reduces manual effort. Evolve the architecture: You’ll identify ways to modernise our systems, managing trade-offs to keep them dependable as they scale. Advocate for quality: You’ll be a sounding board for the team, using code reviews and design sessions to advocate for better engineering practices. Expand your scope: You’ll join a growing team that supports emerging leaders, offering you opportunities to lead projects end-to-end, developing your commercial judgement.

The DE Tech team is a growing engineering team consisting of three smaller cross-functional teams. The teams build and maintain various systems – including tools for underwriting, notifications, and account management – that power iwoca’s German market. They support more than 300 colleagues across sales, credit, and collections who rely on these tools every day. As the German business grows, these teams are moving beyond small improvements and into reworking how work is done. By reducing manual steps and improving how information flows through the company, they directly influence how quickly other teams can act, how reliably iwoca can support its customers, and where we can most effectively spend human effort.