Senior Full Stack (Java/React) Engineer

Luxoft Germany; Kraków; Hybrid; PLN 240,000 - 320,000; Full time

Job summary

Luxoft Germany is seeking a senior Full-Stack Developer (Java + React) to join a client team building a new AI-enabled application platform in the investment banking domain. You will design and implement scalable back-end services with Java/Spring Boot and rich front-end with React/TypeScript, integrating AI features and maintaining high-quality delivery.

The role emphasizes clean code, agile methods, mentoring, and collaboration with QA, product managers, and architects to deliver end-to-end

Qualifications

• 8+ years of professional software development experience.
• 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.
• Hands-on experience with GitHub Copilot or AI coding assistants.
• Knowledge of generative AI, prompt engineering, and integrating LLM APIs.
• Strong SQL and relational database skills.
• Experience in automated testing (JUnit, Jest, RTL).
• Familiarity with CI/CD pipelines and Git-based workflows.
• Clean coding skills and problem-solving ability.
• Familiarity with agile practices (Scrum, Kanban).
• Good communication across teams.

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 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 on both front end and back end.
• Participate in agile ceremonies (Scrum/Kanban), refinement, planning, reviews and retrospectives.
• Work with QA, product managers, architects and stakeholders to deliver high-quality work.

Skills

Java

Spring Boot

React

TypeScript/JavaScript

HTML/CSS

REST APIs

SQL

Automated testing

CI/CD

Agile practices

AI coding tools

Gen AI / Prompt engineering

Communication

Code reviews

Tools

GitHub Copilot

Job description

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 TypeScriptUse AI-assisted development tools such as GitHub Copilot to speed up delivery while keeping quality and security highDesign and integrate generative AI features into business applications, including prompt engineering, LLM integration and evaluation of model outputsDefine and consume RESTful APIs, and communicate requirements and constraints clearly across teamsAdvise and guide the team on architecture, design decisions and best practices, including the responsible use of AI toolsMentor developers and raise the team's technical level through code reviews and pair programmingTranslate business and product requirements into robust end-to-end technical solutionsApply clean code principles and help improve engineering standards, tooling and CI/CD pipelinesWrite and maintain automated tests (unit, integration, end-to-end) on both front end and back endTake an active part in agile ceremonies (Scrum/Kanban), including refinement, planning, reviews and retrospectivesWork closely with QA, product managers, architects and business stakeholders to deliver high-quality work that fits business needsSupport and improve existing applications in a fast-paced, enterprise investment-banking environment

SKILLS

Must have

• At least 8 years of professional software development experience, including long-term projectsStrong hands-on experience with Java (Java 11+) and Spring / Spring BootStrong hands-on experience with React, TypeScript/JavaScript, HTML and CSSProven experience delivering full-stack features end to end, from UI to back-end services and the databaseHands-on experience with GitHub Copilot or similar AI coding assistants in daily developmentPractical knowledge of generative AI and prompt engineering, including integrating LLM APIs (e.g. OpenAI, Azure OpenAI) into applicationsStrong SQL skills and experience with relational databasesExperience in automated testing (JUnit, Jest, React Testing Library or similar)Familiarity with CI/CD pipelines and Git-based workflowsClean coding skillsExcellent problem-solving skillsFamiliarity with agile practices (Scrum, Kanban, etc.)Good communication skills and the ability to state requirements clearly to other teams

Nice to have

.Hands-on experience with Sybase (ASE and/or IQ), including stored procedures and performance tuningKnowledge of the collateral management and margin domain (e.g. margin calls, ISDA/CSA, initial and variation margin, SIMM)Experience in investment banking or capital marketsExposure to RAG architectures, vector databases or AI agent frameworksWorking knowledge of Unix/Linux and shell scripting