Senior Full Stack (Java/React) Engineer

📍 hybrid work - 3 days/week from the office Fabryczna Office Park, Krakow Project Description: We're looking for a senior Full-Stack Developer (Java + React) to join our client's team and help build a new AI-enabled application platform. The team works with modern AI-assisted tools such as GitHub Copilot and generative AI, and cares about clean code, agile methods and high-quality delivery. The client is in the investment banking industry, and the platform supports collateral and margin management. Responsibilities: Design, develop and maintain scalable back-end services and APIs using Java (Spring Boot) Build responsive, high-performance front-end applications using React and TypeScript Use AI-assisted development tools such as GitHub Copilot to speed up delivery while keeping quality and security high Design and integrate generative AI features into business applications, including prompt engineering, LLM integration and evaluation of model outputs Define and consume RESTful APIs, and communicate requirements and constraints clearly across teams Advise and guide the team on architecture, design decisions and best practices, including the responsible use of AI tools Mentor developers and raise the team's technical level through code reviews and pair programming Translate business and product requirements into robust end-to-end technical solutions Apply clean code principles and help improve engineering standards, tooling and CI/CD pipelines Write and maintain automated tests (unit, integration, end-to-end) on both front end and back end Take an active part in agile ceremonies (Scrum/Kanban), including refinement, planning, reviews and retrospectives Work closely with QA, product managers, architects and business stakeholders to deliver high-quality work that fits business needs Support and improve existing applications in a fast-paced, enterprise investment-banking environment Mandatory Skills Description: At least 8 years of professional software development experience, including long-term projects Strong hands-on experience with Java (Java 11+) and Spring / Spring Boot Strong hands-on experience with React, TypeScript/JavaScript, HTML and CSS Proven experience delivering full-stack features end to end, from UI to back-end services and the database Hands-on experience with GitHub Copilot or similar AI coding assistants in daily development Practical knowledge of generative AI and prompt engineering, including integrating LLM APIs (e.g. OpenAI, Azure OpenAI) into applications Strong SQL skills and experience with relational databases Experience in automated testing (JUnit, Jest, React Testing Library or similar) Familiarity with CI/CD pipelines and Git-based workflows Clean coding skills Excellent problem-solving skills Familiarity with agile practices (Scrum, Kanban, etc.) Good communication skills and the ability to state requirements clearly to other teams Nice-to-Have Skills Description: .Hands-on experience with Sybase (ASE and/or IQ), including stored procedures and performance tuning Knowledge of the collateral management and margin domain (e.g. margin calls, ISDA/CSA, initial and variation margin, SIMM) Experience in investment banking or capital markets Exposure to RAG architectures, vector databases or AI agent frameworks Working knowledge of Unix/Linux and shell scripting Languages: English: C1 Advanced