Senior Fullstack Engineer with Java/ React/ TypeScript (f/m/x)

Join the team developing an advanced planning platform that is scaled across multiple markets and supports complex business processes. You will work on a large-scale product where performance, reliability, and further development are key. The role involves developing both the backend and frontend layers, with a focus on building a cohesive and scalable solution.

The project is in a phase of intensive development and scaling, which gives a real impact on architecture and technological direction. An essential part of the job will also be the active use of AI and LLM tools, which are an integral part of the development environment and support the daily work of the team.

Expected availability to work from the office in Katowice – 1 day per quarter.

Your tasks

• Designing and implementing backend solutions (REST API, scheduling logic, core modules)
• Developing the frontend application (React, Next.js, SSR)
• Building and maintaining integrations between systems (API, service communication)
• Utilizing AI and LLM tools for automation and optimization of development work
• Co-creating system architecture and making technological decisions
• Implementing resource scheduling and allocation mechanisms
• Developing automated tests (unit, integration, e2e)
• Building and maintaining CI/CD pipelines (GitHub Actions, Gradle)
• Managing the application lifecycle (deployments, monitoring, optimization)
• Collaborating with the Product Owner and product team on the roadmap and priorities

Requirements

• Minimum 8 years of programming experience (preferred fullstack profile)
• Solid experience in Java and Spring Boot (building enterprise applications, designing APIs, working with backend architecture)
• Practical knowledge of React.js and/or Next.js
• Good knowledge of TypeScript / JavaScript
• Ability to design and implement REST APIs
• Practical experience with containerization and orchestration using Docker, Kubernetes
• Knowledge of cloud environments (preferably Azure)
• Ability to create automated tests and ensure code quality
• Actively utilizing AI and LLM tools in development work (e.g., supporting implementation, refactoring, debugging, task automation)
• Willingness to work from the office in Katowice 1 day per quarter

Nice to have

• Ability to develop backend in Node.js on a larger scale (service architecture, performance)
• Knowledge of Vue.js
• Previous work with Terraform and infrastructure as code
• Knowledge of CI/CD tools (GitHub Actions or others) and Gradle
• Experience in building custom workflows and automation based on AI/LLM

Job no. JOB-3X6EA Sii ensures that all hiring decisions are made solely on the basis of qualifications and competence. We are committed to equal and fair treatment of all, regardless of legally protected characteristics. At Sii, we promote a diverse and inclusive work environment, in full compliance with applicable anti-discrimination laws.

Benefits For You

• Great Place to Work
• Solid financial situation
• Contracts with the biggest brands
• Centre of internal trainings
• Many experts you can learn from
• Open and accessible management team
• Profit sharing
• Passion Sponsorship program
• Regular integration events and trips
• Comfortable and well-equipped offices
• MySii app
• Medical care