Senior UI Engineer

Luxoft; Kraków; On-site; PLN 260,000 - 420,000; Full time

Job summary

Luxoft Kraków is seeking a proactive Senior Front-end Engineer to contribute to a high-performance SPA built with React 17+. You will design and implement rich client-side features for a data-dense onboarding workflow, collaborating closely with business stakeholders and backend teams.

You will own components, optimize performance, ensure accessibility, and mentor peers, while delivering robust UI across complex workflows in a fast-paced, Agile environment.

Qualifications

• 8+ years of practical front-end experience building production React applications.
• Advanced proficiency in React (17+), JavaScript, HTML5, and component-based architecture; Redux is a plus.
• Strong understanding of RESTful APIs and communication with backend teams.
• Experience delivering complex, data-dense UIs with accessible, scalable styling.
• Hands-on with testing: unit/integration/e2e (Jest, RTL, Cypress) and CI/CD pipelines.

Responsibilities

• Develop JavaScript code for a large-scale, rich internet and modular application using React 17+.
• Create new components for the business-driven library to represent client data.
• Collaborate closely with business stakeholders, server-side developers, UX designers, and QA professionals.
• Master state-of-the-art technologies and a complex business domain.
• Solve challenging problems in elegant ways.
• Share knowledge across the project team.
• Contribute to the quality of software delivered in each development iteration.

Skills

React 17+

JavaScript ES2015+

HTML5

CSS/Less

Redux

REST API

Testing (Jest/RTL/Cypress)

CI/CD (GitLab)

Agile (Scrum/Kanban)

Cross-team collaboration

Accessibility

Tools

Jest

RTL

Cypress

Webpack/Vite

GitLab CI/CD

React tooling

Job description

Project description

We are developing a high-performance workflow system for the client's onboarding domain. This system focuses on capturing various types of data from clients based on JSON schema. The project involves extending the workflow system functionalities, including a single-page application (SPA) written in React 17+ and a business-oriented components library that is reused by multiple applications to capture data. The UI team and most of the project team is co-located in Krakow - it means effective and close collaboration. We are looking for a proactive individual who can suggest improvements to the library and the application and take ownership of their work.This person will collaborate with the business team and backend developers to discuss domain-level changes and will not shy away from participating in discussions.

Responsibilities

• Develop JavaScript code for a large-scale, rich internet and modular application using React 17+.
• Create new components for the business-driven library to represent client data.
• Collaborate closely with business stakeholders, server-side developers, user experience designers, and quality assurance professionals.
• Master state-of-the-art technologies and a complex business domain.
• Solve challenging problems in elegant ways.
• Share knowledge across the project team.
• Contribute to the quality of software delivered in each development iteration.

SKILLS

Must have

• At least 8+ years of practical experience in front-end development, with a proven track record of long-term engagements building and delivering production React applications.
• Advanced proficiency in React (17+), modern JavaScript (ES2015+), HTML5, and clean, component-based architecture; experience with Redux is a plus.
• Solid understanding of RESTful API integration patterns and clear communication of requirements to backend teams.
• At least two complex, user-facing applications successfully delivered to production, ideally involving rich interactive UIs, state-heavy workflows, or data-dense interfaces.
• Practical, hands-on experience with styling at scale using CSS3/Less (not being afraid to style applications), responsive design, and cross-browser compatibility.
• Strong grasp of front-end engineering fundamentals: component design, state management, performance optimization, accessibility, and maintainable code.
• Solid understanding of testing practices: unit, integration, and end-to-end testing of UI applications (e.g., Jest, React Testing Library, Cypress), plus CI/CD pipelines (e.g., GitLab CI/CD).
• Ability to evaluate trade-offs and select appropriate libraries, frameworks, and architectural patterns for a given problem.
• Experience with PoC development and iterating quickly based on results.
• Excellent problem-solving abilities, clean coding skills, and strong attention to detail.
• Familiarity with Agile development practices (Scrum, Kanban, etc.) and excellent communication and collaboration skills.
• Experience using agentic LLMs to support the development process.

Nice to have

• Experience with Cypress or similar end-to-end testing frameworks.
• Experience with Figma and translating UI designs into production code.
• Understanding of UX principles and approaches.
• Familiarity with micro-frontend architectures and build tooling (e.g., webpack, Vite).