Principal Java Engineer - Retail

Mindera; City Of London; Hybrid; GBP 70,000 - 95,000; Full time

Job summary

A leading technology company in London seeks a Principal Java Engineer with extensive experience in Java and Retail. This six-month contract requires expertise in Spring Boot and cloud-native development. You will lead technical discussions, mentor engineers, and ensure robust and secure systems. Join a friendly team dedicated to quality and collaboration.

Benefits

Competitive Rates

Possibility of extension

Friendly and welcoming team

Opportunity to work with leading Retailers

Qualifications

• Proven experience as a Principal Java Engineer in backend-heavy environments.
• Strong experience in Java 17+, ideally with Spring Boot or Micronaut.
• Hands-on knowledge of Kafka and event-driven architecture.
• Solid understanding of payment systems and PSP integrations.
• Experience with cloud infrastructure (Azure preferred) and Kubernetes.
• Working knowledge of regulatory standards (PCI DSS, SCA, PSD2).
• Strong communication skills to explain complex concepts.

Responsibilities

• Lead technical deep dives and propose solutions.
• Write high-quality Java code, supporting secure transactions.
• Develop cloud-native systems using Terraform and Kubernetes.
• Champion secure coding practices across services.
• Mentor junior engineers and establish best practices.

Skills

Java 17+

Spring Boot

Micronaut

Kotlin

Kafka

Cloud infrastructure (Azure)

CI/CD

Kubernetes

Agile/Scrum

Tools

Terraform

GitHub Actions

OpenTelemetry

Dynatrace

Job description

At Mindera, we craft software with people we love. We’re looking for a Principal Java Engineer with strong Retail experience who can join our crew!

Please note: This is a six month contract that sits outside IR35. You will be required to work in Paddington 3 days a week.

What does the role involve?

• Lead technical deep dives and knowledge sharing in the teams, anticipating challenges and proposing solutions
• Start influencing product and business decisions

Hands-on Software Development:

• Write high-quality Java code using frameworks such as Spring Boot or Micronaut.
• Build robust services that support secure, high-volume payment transactions.
• Develop integrations with acquiring banks, payment gateways, and fraud detection tools.

Cloud & DevOps Practices:

• Build and support cloud-native systems on the cloud (preferably Azure) using Terraform and Kubernetes.
• Manage CI/CD pipelines using GitHub Actions and ensure smooth delivery to production.
• Own monitoring, alerting, and observability, using tools like OpenTelemetry and Dynatrace.

Security & Compliance:

• Champion secure coding practices and data protection across services.

Collaboration & Mentoring:

• Work closely with product owners, engineering leads, and other stakeholders to shape technical solutions.
• Mentor and support more junior/mid/senior engineers, driving technical excellence across the board.
• Help establish and promote best practices around code review, testing, delivery, and operational support.

Continuous Improvement:

• Continuously improve platform reliability, performance, and cost-efficiency.
• Stay up-to-date with technology trends and proactively identify innovation opportunities.

Requirements

• Proven experience as a Principal Java Engineer in backend-heavy environments in teams having multiple levels of engineering.
• Strong experience in Java 17+, ideally with experience in using Spring Boot or Micronaut. Kotlin experience is a bonus. If the applicant does not have experience they must show willingness to learn Kotlin.
• Hands-on knowledge of Kafka, event-driven architecture, enterprise integration patterns and Microservices.
• Solid understanding of payment systems and PSP integrations, including fraud, tokenisation, and settlement flows.
• Experience with cloud infrastructure (Azure preferred), CI/CD, and Kubernetes.
• Working knowledge of regulatory and compliance standards (PCI DSS, SCA, PSD2).
• Strong communication skills and the ability to explain complex technical concepts to a range of audiences.
• Experience working in Agile/Scrum teams with a DevOps culture and test-driven mindset.

Benefits and Perks

• Competitive Rates
• Six month contract outside IR35 with possibility of extension
• Friendly and welcoming team
• Opportunity to work with one of the UK's leading Retailers

At Mindera we use technology to build products we are proud of, with people we love.

Software Engineering Applications, including Web and Mobile, are at the core of what we do at Mindera. We partner with our clients, to understand their product and deliver high performance, resilient and scalable software systems that create an impact on their users and businesses across the world.

You get to work with a bunch of great people, where the whole team owns the project together. Our culture reflects our lean and self‑organisation attitude. We encourage our colleagues to take risks, make decisions, work in a collaborative way and talk to everyone to enhance communication.

We are proud of our work and we love to learn all and everything while navigating through an Agile, Lean and collaborative environment.

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