OverviewThis range is provided by Fynity. Your actual pay will be based on your skills and experience — talk with your recruiter to learn more.Principal Software Engineer (Java)London – 1 day a week onsiteJoin a FinTech Powering the Future of PaymentsAre 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 DoingYou’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 transactionsWork with Java 17+, Spring WebFlux, AKKA, Kafka, and moreWrite clean, testable code using TDD and BDDContribute to architectural decisions in a fast-evolving codebaseCollaborate within Agile teams (Kanban/Scrum) What You BringWe’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 resilienceAgile mindset, with TDD/BDD and CI/CD experienceBonus: 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 YouWork with cutting-edge tech on globally impactful systemsHybrid working – 1 day a week (or more if you’d like!)Opportunity to collaborate with major global banksFast-paced, product-led environment where your voice mattersIf 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.Employment and SenioritySeniority level: Mid-Senior levelEmployment type: Full-timeJob function: Engineering, Information Technology, and OtherIndustries: Banking, Financial Services, and Software Development #J-18808-Ljbffr