Principal Backend Engineer - Java.

Principal Backend Engineer – Java

Location: London (Hybrid) | Practice Area: Technology & Engineering | Type: Permanent

Build scalable backend solutions that help shape the future of financial services.

The Role

Capco is growing our Engineering team, and we’re looking for experienced Principal Backend Engineers with strong Java skills and a passion for delivering innovative solutions in financial services.

As a Principal Backend Engineer at Capco, you’ll contribute to high-impact, client-facing projects and work with cloud-native technologies across different domains within Financial Services & Energy. You’ll collaborate with talented engineers, contribute to architecture and engineering decisions, and have access to industry-leading learning and development opportunities.

You’ll also use approved AI tools, automation and AI-enabled engineering workflows where appropriate to improve development speed, quality and productivity, while applying human judgement, responsible AI guardrails and appropriate review.

What You’ll Do

• Build and deliver scalable backend services using Java 11, 17+, designing APIs and microservices for enterprise systems.

• Work across cloud platforms, particularly AWS, applying cloud-native deployment techniques and contributing to architecture and solution design.

• Develop robust automated test coverage across unit, component, integration, end-to-end and performance testing.

• Collaborate with clients, product managers and engineers in agile teams to design, deliver and troubleshoot large-scale distributed systems.

• Use approved AI tools, automation and AI-enabled workflows to support engineering activities such as development, testing, troubleshooting and documentation, with appropriate human review and responsible AI controls.

What We’re Looking For

• Expertise in Java 11, 17+ and Spring Boot, with experience designing and delivering large-scale enterprise backend systems.

• Experience with cloud-native and distributed architectures, including microservices, event-driven patterns and CQRS, preferably deployed within AWS.

• Experience with CI/CD, Infrastructure as Code such as CloudFormation, and SQL and NoSQL databases.

• Experience with Kafka, Java streaming, automated testing and troubleshooting distributed systems.

• Curiosity and practical experience using approved AI, GenAI or AI-enabled development tools to improve engineering productivity, with an understanding of human-in-the-loop review, responsible AI, guardrails and escalation where required.

Bonus Points For

• An appetite to contribute to the wider Capco business through activities such as thought leadership, supporting RFPs and coaching or mentoring engineering colleagues.

• Proficiency with GitLab for CI/CD processes and experience writing automation test cases in Cucumber using Behaviour Driven Development (BDD).

• AWS Certified Solutions Architect – Associate or Professional level certification.

• Knowledge of security best practices, including IAM Roles and KMS.

• Experience exploring responsible AI-enabled engineering practices, including automation or Agentic AI workflows, while maintaining appropriate review, auditability and human oversight.

Why Join Capco

• Deliver high-impact technology solutions for Tier 1 financial institutions.

• Work in a collaborative, flat, and entrepreneurial consulting culture.

• Access continuous learning, training, and industry certifications.

• Be part of a team shaping the future of digital financial services.

• Help shape the future of digital transformation across FS & Energy.

We offer a competitive, people-first benefits package designed to support every aspect of your life:

Benefits

• Core Benefits: Discretionary bonus, competitive pension, health insurance, life insurance and critical illness cover.

• Mental Health: Easy access to CareFirst, Unmind, Aviva consultations, and in-house first aiders.

• Family-Friendly: Maternity, adoption, shared parental leave, plus paid leave for sickness, pregnancy loss, fertility treatment, menopause, and bereavement.

• Family Care: 8 complimentary backup care sessions for emergency childcare or elder care.

• Holiday Flexibility: 5 weeks of annual leave with the option to buy or sell holiday days based on your needs.

• Continuous Learning: Your growth, your way – minimum 40 hours of training annually. Take your pick from workshops, certifications and e-learning. Plus, a Business Coach assigned from Day One provides one-to-one guidance to support your goals and accelerate your development.

• Healthcare Access: Convenient online GP services.

• Extra Perks: Gympass (Wellhub), travel insurance, Tastecard, season ticket loans, Cycle to Work, and dental insurance.

Inclusion at Capco

We’re committed to making our recruitment process accessible and straightforward for everyone. If you need any adjustments at any stage, just let us know – we’ll be happy to help. We value each person’s unique perspective and contribution. At Capco, we believe that being yourself is your greatest strength. Our #BeYourselfAtWork culture encourages individuality and collaboration – a mindset that shapes how we work with clients and each other every day.

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