Senior C# Software Engineer – London

The engineering challenge

You will design and evolve the services that power core banking products. The systems you help build process thousands of financial transactions every day. They must be scalable, resilient and secure. When money moves, it has to work. Every time.

But this role goes beyond implementation.

You will shape technical direction. Influence cross-team initiatives. Own complex, high-impact work from concept through to production. You will help decide not just how we build, but what we build and why.

This is senior in impact, not just title.

We’re growing across several of our product-engineering tribes at Zopa, with current opportunities in Current Accounts, Lending, Credit Cards and Product Enablement.

We care deeply about great engineering, which is why our core stack is Kotlin, running on a modern platform with Kafka, Kubernetes, Docker and AWS Aurora Postgres. But great engineers aren’t defined by a single language which is why we are agnostic with our hiring.

We want the right people, not the 'right' language, so if you come from a C#/.NET background, bring solid fundamentals, and have an appetite for learning something new, we’ll invest in you, help you grow your skills and confidently step into our Kotlin ecosystem.

Your impact:

• Owning complex initiatives end to end, from idea to measurable outcome

• Designing scalable backend systems that stand up to real-world scale and complexity

• Making architectural decisions that balance immediate delivery with long-term sustainability

• Bringing structure and clarity to ambiguous problems

• Influencing prioritisation and trade-offs across teams

• Raising the bar for engineering quality, reliability and accountability

• Mentoring engineers and strengthening overall team capability

• Driving continuous improvement in how we build and operate systems

Your toolkit:

• You'll work with C#, Kafka, Kubernetes, Docker, AWS Aurora Postgres, and other modern technologies. If you haven't worked with all of these, we value skilled engineers with a willingness to learn.
• A track record of delivering high-impact, complex systems in production environments
• Strong testing discipline, with a commitment to strictly following Test-Driven Development (TDD)
• Strong systems thinking and architectural judgement
• The ability to navigate ambiguity and turn complexity into clear, actionable plans
• Confidence making data-informed technical decisions with long-term consequences in mind
• Experience influencing beyond your immediate team
• A deep customer focus and a bias toward measurable outcomes
• Experience mentoring others and amplifying team impact
• Ownership beyond your own output

We’ll support your transition and cross-training into a JVM/Kotlin environment. What matters most to us is how you think, how you approach problem-solving, and the scale and impact of what you’ve built.

Our engineering culture:

• Customer impact over unnecessary complexity
• Team success over individual heroics
• Operational ownership, not just feature delivery
• Continuous improvement through honest feedback

Added bonus:

• Experience with fintech or banking is a plus, but we value problem-solvers from all backgrounds