Principal Java Software Engineer

JR United Kingdom; Swindon; Hybrid; GBP 70,000 - 100,000; Full time

Job summary

A leading payments consultancy seeks a Principal Java Software Engineer in Swindon to spearhead the development of high-throughput payment systems. In this hybrid role, you will leverage your extensive Java expertise and join a dynamic team focused on real-time transactions that transform the banking landscape.

Benefits

20% performance bonus

Opportunity to work with cutting-edge tech

Hybrid working – 1–2 days/week in the London office

Collaboration with major global banks

Fast-paced, product-led environment

Qualifications

• Strong hands-on experience with modern Java technologies.
• Knowledge of event-driven architecture and real-time messaging systems.
• Familiarity with TDD/BDD and CI/CD methodologies.

Responsibilities

• Design and build scalable, high-availability systems.
• Collaborate within Agile teams and make architectural decisions.
• Write clean, testable code using TDD and BDD.

Skills

Java 11+

Reactive Programming

Asynchronous request handling

Agile mindset

Tools

Spring WebFlux

Kafka

AKKA

Job description

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Principal Java Software Engineer, swindon, wiltshire

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Client:

Fynity

Location:

swindon, wiltshire, United Kingdom

Job Category:

Other

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EU work permit required:

Yes

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Job Views:

3

Posted:

26.06.2025

Expiry Date:

10.08.2025

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Job Description:

Principal Java Software Engineer

London (Hybrid – 1–2 days/week onsite)

? Join a FinTech Powering the Future of Payments

Are you an experienced Senior/Principal Java Software Engineer who thrives in a fast-paced, agile environment? 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 financial institutions.

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 join 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

• ? 20% performance bonus
• ? Work with cutting-edge tech on globally impactful systems
• ? Hybrid working – 1–2 days/week in a London office
• ? Opportunity to collaborate with major global banks
• ? Fast-paced, product-led environment where your voice matters

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