Java Lead Principal engineer

Java Principal / Lead engineer – Java, AWS, MongoDB, Architecture, design – UK remote, Outside contract

2 month initial plus extension We are working with a business who are rebuilding their core platform from the ground up and are looking for a Lead Java engineer who’s up for a real challenge.

Their system was originally built externally, and they\’ve now brought it fully in-house. So, your mission is to get under the hood, untangle what’s there, and help them design something better — cleaner, faster, and built to scale. Someone with a forensic mind who is then able to get on with the fix. You will understand the architecture and be able to unpin what they have to design and build a better solution.

You’ll work with the Tech Manager, Product Owner, and Solution Architect to modernise the platform and shape the next generation of features.

What You’ll Be Doing

• Own the project entirely, end to end — from discovery and design to delivery and optimisation.
• Work across the stack using Java, React, AWS, MongoDB, and Elasticsearch.
• Refactor and re-engineer core components to make the platform faster, more reliable, and easier to extend.
• Collaborate closely with product and architecture teams.
• Review code, mentor teammates, and bring fresh thinking to the table.
• Write clean, well-documented code that’s built to last.

Experience

• Strong experience within the Java AWS stack
• Experience modernising or replatforming legacy systems.
• Familiarity with microservices, CI/CD, or serverless architectures.
• An interest in building scalable, high-performing distributed systems.
• A great understanding of modern software architecture, design principles and data structures.
• Practical experience with Java, React, MongoDB and AWS
• Curiosity and persistence — you enjoy cracking tough problems and simplifying complexity.
• The ability to balance autonomy with collaboration

If this sounds like you then let me know and we can set up a call.

2 stage interview process completed in the next 2 weeks and immediate start thereafter