Principal Backend Engineer Java Spring Boot AWS

Client Server Ltd.; Greater London; Hybrid; GBP 100,000 - 120,000; Full time

Benefits offered by this job

Pension

Life Assurance

Private medical care for you and your…

Travel Insurance

Charitable giving

Gym membership for you and your family

Job summary

Client Server Ltd. in London is seeking a Principal Backend Engineer to take technical ownership of complex Java projects, lead client engagements and drive modernisation initiatives.

You'll combine hands-on engineering with leadership, guiding teams in cloud migration, microservices, REST APIs and CI/CD while delivering measurable client outcomes.

Qualifications

• Experience in a financial services or Fintech environment.
• Strong Java development skills including multi-threading and concurrency.
• Experience with Spring Boot and microservices environments.
• Good knowledge of REST APIs.
• Solid understanding of AWS.
• Strong fundamentals in OOP, data structures and design patterns.
• Familiar with DevOps and CI/CD pipelines.

Responsibilities

• Lead technical projects and client engagements from design through to delivery.
• Develop scalable Java applications using Spring Boot and microservices.
• Modernise and migrate legacy systems to AWS.
• Design and work with REST APIs and distributed systems.
• Introduce and improve CI/CD and DevOps practices.
• Provide technical expertise and guidance to clients and engineering teams.

Skills

Java

Spring Boot

AWS

Microservices

REST APIs

CI/CD

DevOps

Multi-threading

OOP

Design Patterns

Job description

London, Greater London | £100k - £120k per year

Principal Backend Engineer / Developer (Java Spring Boot AWS) London / WFH to £120k

Are you an experienced Java Software Engineer who enjoys taking technical ownership, leading projects and working directly with clients?

You could be progressing your career at a global technology consultancy, working on complex, long-term transformation projects, primarily within the financial services sector.

As a Principal Backend Engineer, you'll lead the design and delivery of high impact technology projects, helping clients modernise legacy systems, migrate to AWS and introduce modern CI/CD and cloud deployment practices. You'll combine hands‑on engineering with technical leadership, problem solving and client engagement.

You'll work alongside a highly collaborative team focused on engineering excellence, continuous improvement and delivering meaningful outcomes for clients.

What you'll be doing:

• Leading technical projects and client engagements from design through to delivery
• Developing scalable Java applications using Spring Boot and microservices
• Modernising and migrating legacy systems to AWS
• Designing and working with REST APIs and distributed systems
• Introducing and improving CI/CD and DevOps practices
• Providing technical expertise and guidance to clients and engineering teams

Location / WFH:

There's a hybrid work from home policy with three days a week in the London, City office (or at client sites), you'll join a friendly, diverse, upbeat team.

About you:

• You have experience within a financial services or Fintech environment
• You have strong Java development skills including multi-threading and concurrency
• You have experience with Spring Boot and microservices environments
• You have a good knowledge of REST APIs
• You have a good understanding of AWS
• You have a thorough understanding of software development and Computer Science fundamentals such as Object Oriented Programming, Data Structures and Design Patterns
• You are familiar with DevOps, CI/CD pipelines
• You're collaborative, enjoy problem solving and interacting with clients

What's in it for you:

As a Principal Backend Engineer / Developer you will earn a highly competitive package:

• Salary to £120k
• Pension, Life Assurance, Income Protection
• Private medical care for you and your family, including mental health
• Travel Insurance
• Charitable giving
• Gym membership for you and your family