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Fynity

Principal Software Engineer

Hybrid

London, United kingdom

£ 115,000 /year

Senior

Full Time

12-11-2025

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Skills

Java CI/CD Kanban Scrum Architecture Programming Agile Spring Kafka

Job Specifications

Principal Software Engineer (Java)

London – 1 day a week onsite

Join a FinTech Powering the Future of Payments

Are you a seasoned individual contributor looking for a step up into a senior position within a high-performing team within the world of Banking/Payments? Are you passionate about high-throughput, real-time systems? This is your opportunity to help shape the core technology that powers instant payments for some of the world’s largest Banks.

We’re hiring on behalf of a leading payments consultancy, delivering cutting-edge solutions that integrate seamlessly with bank infrastructure to enable real-time, secure transactions across the globe.

What You’ll Be Doing

You’ll be the focal point of a high-performing engineering team building asynchronous, event-driven systems using modern Java technologies.

Design and build scalable, high-availability systems processing millions of real-time transactions
Work with Java 17+, Spring WebFlux, AKKA, Kafka, and more
Write clean, testable code using TDD and BDD
Contribute to architectural decisions in a fast-evolving codebase
Collaborate within Agile teams (Kanban/Scrum)

What You Bring

We’re looking for engineers who are pragmatic, performance-focused, and thrive on solving complex distributed systems problems.

Strong hands-on experience with Java 11+ (ideally Java 17)
Solid knowledge of Reactive Programming (e.g., Spring WebFlux, AKKA)
Experience with event-driven architecture, real-time messaging systems (Kafka, JMS)
Familiarity with asynchronous request handling, scalability, and system resilience
Agile mindset, with TDD/BDD and CI/CD experience

Bonus: Background in Banking/Payments is helpful but not required – if you’ve built high-performance, real-time systems, we want to talk to you.

What’s In It for You

£100,000 – £115,000 base salary (DOE)
20% bonus
Work with cutting-edge tech on globally impactful systems
Hybrid working – 1 day a week (or more if you’d like!)
Opportunity to collaborate with major global banks
Fast-paced, product-led environment where your voice matters

If you're a motivated Senior/Principal/Staff Java Software Engineer ready to tackle complex challenges and deliver meaningful change, hit apply – and shape the future of payments with us.

About the Company

Fynity is a talent solutions partner with a mission to inspire futures without limits. We connect organisations with the tech talent they need to drive growth and success. Leveraging deep industry knowledge, established candidate networks and the latest cutting-edge AI-enabled search tools, we provide access to top talent in the fast-growing fields of Cloud, Data & AI, Software Engineering and other Emerging Tech. Our solutions are crafted to tackle difficult talent challenges in the ever-evolving tech landscape, reducing... Know more