Principal Full-Stack Engineer (Java,React,LLMs)
13 days ago
Sheffield
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.