Principal Full-Stack Engineer (Java,React,LLMs)

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

Why join us?

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.

Job Details

Company
RE Partners
Location
England, United Kingdom
Posted