Senior Software Engineer (FinTech & Greenfield) (London, ENG)

The company

A well-established UK payments business is being separated from its parent, a major UK bank, to become a standalone technology company backed by a global investment partner. It already handles a large share of UK card payments every day, in supermarkets, fuel stations, on public transport and elsewhere. That means it already has its customers and its funding. What it’s building now is the technology.

Why it’s interesting

• Greenfield work. The old mainframe and batch systems are being replaced, not migrated. Hundreds of millions of pounds have been committed to rebuilding the platform.
• Early influence. The product engineering organisation is growing to 100–200 engineers across about 12 teams, with a smaller platform team of 20–30. Few hires have been made so far, so early joiners help set the standards and the culture.
• It already ships. The first production releases went live in September 2026. In the month before, a team of 46 engineers averaged about 60 deploys a day. The aim is for every new engineer to commit to production on day one.
• It’s a permanent team. Consultancies got the platform started, and the plan is a permanent in-house team of people who want to build something together.
• AI is part of the build. A dedicated team is building an AI-driven delivery workflow, and AI tools are welcome in the hiring process.

Tech stack

• Back end: Kotlin (about 90%), Rust for time-critical, high-throughput services
• Front end: TypeScript, React and React Native
• Infrastructure and data: AWS, Databricks, NATS messaging
• Delivery: GitHub CI/CD, Kubernetes, Istio
• Architecture: event-driven, real-time and asynchronous, with no batch jobs. They build what sets them apart and buy the rest.

The roles

• Software Engineer: Associate through Mid, Senior, Staff and Principal
• Engineering Lead: leading a single team while staying hands-on, or leading leads across a product area
• No need to pick a level. Your level is agreed with you during the process.

Who they’re looking for

• Experience with distributed, cloud-native systems. Payments experience is a bonus, not a requirement.
• Experience building something from zero to one: a product, a platform, a team or a company
• Comfort with ambiguity and with making decisions on imperfect information
• Recent Kotlin or Java experience. An interest in Rust is a plus.
• Low ego: confident enough to hold an opinion and humble enough to change it

Package and logistics

• Salary (indicative):
• Mid: £60–80k
• Senior: £80–120k
• Staff/Principal: up to around £130k plus bonus
• Benefits: in line with a major UK bank’s package
• Location: Central London, 3 days a week in the office
• Right to work: visa sponsorship isn’t available