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- Tasks: Lead the design and development of scalable backend services and optimise high-performance APIs.
- Company: Join a leading U.S. banking institution focused on impactful engineering.
- Benefits: Competitive salary, mentorship opportunities, and a dynamic work environment.
- Other info: Great career growth potential in a diverse and collaborative team.
- Why this job: Work with cutting-edge AI technologies and make a real difference in digital transformation.
- Qualifications: Strong Java and React experience, plus hands-on LLM/AI skills.
The predicted salary is between 80000 - 100000 £ per year.
We’re hiring a Principal Full-Stack Engineer to join one of the largest banking institutions in the U.S. - a highly complex, high-impact environment where engineering decisions truly matter.
This role is ideal for someone who combines deep backend expertise in Java with strong frontend capabilities in React, and hands-on experience working with LLMs (Claude preferred).
What you’ll be doing:
- Lead the design and development of scalable backend services in Java (Spring Boot)
- Build and optimize secure, high-performance APIs
- Contribute to and guide React-based frontend architecture
- Work hands‑on with LLM/AI technologies (Claude or similar), integrating them into real-world applications
- Drive best practices across code quality, architecture, and performance
- Mentor engineers and support UI developers in delivering high-quality solutions
- Partner with stakeholders to translate business needs into technical execution
- Contribute to system design discussions, code reviews, and continuous improvement
What we’re looking for:
- Strong experience in Java backend development and server‑side architecture
- Solid React experience on the frontend
- Hands‑on experience with LLMs / AI tools and practical implementation
- Experience designing and building scalable, distributed systems
- Strong understanding of APIs, databases, and performance optimization
- Proven ability to lead technically and mentor others
Nice to have:
- Experience with GraphDB, Scala, or complex data processing systems
- Exposure to cloud platforms (AWS, Azure, or GCP)
- Familiarity with CI/CD pipelines and DevOps practices
At RE Partners, we partner with industry leaders to deliver high-impact technology solutions. We’re not a traditional staffing agency - we operate as a true consulting partner, helping organizations navigate complex digital transformations. Our global team, diverse culture, and strong delivery model have made us a trusted partner to Fortune 1000 companies.
If you’re excited about building at scale, working with cutting‑edge AI, and operating at a principal level - let’s connect.
Principal Full-Stack Engineer (Java,React,LLMs) in London employer: RE Partners
Contact Detail:
RE Partners Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Principal Full-Stack Engineer (Java,React,LLMs) in London
✨Tip Number 1
Network like a pro! Reach out to your connections in the industry, especially those who work at the company you're eyeing. A friendly chat can sometimes lead to insider info or even a referral, which can give you a leg up in the hiring process.
✨Tip Number 2
Show off your skills! If you've got a portfolio or GitHub with projects that highlight your Java and React expertise, make sure to share it. Real-world examples of your work can speak volumes about your capabilities and fit for the role.
✨Tip Number 3
Prepare for the technical interview by brushing up on your coding skills and system design principles. Practice common algorithms and data structures, and be ready to discuss how you've tackled challenges in past projects, especially with LLMs.
✨Tip Number 4
Don’t forget to apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we love seeing candidates who take that extra step to connect with us directly.
We think you need these skills to ace Principal Full-Stack Engineer (Java,React,LLMs) in London
Some tips for your application 🫡
Tailor Your CV: Make sure your CV highlights your experience with Java, React, and LLMs. We want to see how your skills align with the role, so don’t be shy about showcasing relevant projects or achievements!
Craft a Compelling Cover Letter: Your cover letter is your chance to shine! Use it to explain why you’re excited about this role and how your background makes you a perfect fit. We love seeing passion and personality in applications.
Showcase Your Leadership Skills: Since this is a principal role, we’re keen on your leadership experience. Highlight any mentoring or team-leading roles you've had, and how you’ve driven best practices in your previous positions.
Apply Through Our Website: We encourage you to apply directly through our website. It’s the best way for us to receive your application and ensures you’re considered for this exciting opportunity. Let’s get started!
How to prepare for a job interview at RE Partners
✨Know Your Tech Stack Inside Out
Make sure you’re well-versed in Java, React, and LLMs like Claude. Brush up on your backend and frontend skills, and be ready to discuss specific projects where you've used these technologies. This will show that you can hit the ground running.
✨Prepare for System Design Questions
Expect to dive deep into system design discussions. Think about how you would architect scalable systems and optimise APIs. Practise explaining your thought process clearly, as this will demonstrate your leadership capabilities and technical expertise.
✨Showcase Your Mentoring Skills
Since the role involves mentoring, be prepared to share examples of how you've guided others in previous roles. Highlight any experiences where you’ve helped junior engineers or collaborated with UI developers to deliver high-quality solutions.
✨Understand the Business Context
Familiarise yourself with the banking industry and the specific challenges it faces. Be ready to discuss how your technical decisions can impact business outcomes. This shows that you’re not just a techie but also understand the bigger picture.