Back-end Developer (JS Stack: Node.js/Nest.js/Express.js)

Description & RequirementsWho we are looking forWe're hiring a Back-end Developer to design and deliver scalable APIs and platform services powering the Olympic & Paralympic digital ecosystem.You'll use Node.js, TypeScript, and frameworks such as Nest.js or Express to build scalable APIs and integrate with React/Next.js front-ends - ensuring robust performance and reliability at global scale. You'll take ownership of architecture, implementation, testing, and deployment - collaborating closely with product managers, designers, and front-end engineers in an international agile team.We adopt an AI-driven engineering mindset - using emerging tools to improve workflows, automate routine tasks, and explore new ways to deliver software. In this role, you'll help define how AI supports and enhances our delivery lifecycle.Required Skills & Experience: 3+ years of commercial experience as a Back-end or Full-stack Developer Expert knowledge of Node.js (Express/Nest.js or similar) Hands-on experience with React 17+ and Next.js 13+, including SSR, CSR, and modern patterns Proficient in TypeScript and modern JavaScript (ES6+) Solid understanding of HTML, CSS, SASS, and responsive web design Strong grasp of API design principles, microservices architecture, and caching strategies Familiar with databases (PostgreSQL, MongoDB, etc.) and ORMs (Prisma, TypeORM) Comfortable with both functional and object-oriented programming paradigms Experience integrating testing frameworks into CI pipelines Curiosity and experience with AI-assisted development tools (e.g., GitHub Copilot, Codeium, Cursor) or automation in testing and delivery pipelines Awareness of how AI and data-driven insights can enhance software quality, developer productivity, and decision-making English B2/C1+ -- able to participate confidently in client discussionsNice to Have Experience with containerized environments (Docker, Kubernetes) Knowledge of cloud platforms (AWS, Azure, GCP) and CI/CD pipelines Exposure to feature flags, observability tools, and analytics Understanding of security best practices, authentication, and authorization (JWT, OAuth2)Your future roleDesign and build enterprise-grade back-end services using Node.js (Nest.js, Express, or similar) Develop and integrate Next.js applications (SSR/CSR, API routes, middleware) Create and maintain RESTful and GraphQL APIs, ensuring performance, scalability, and security Design and optimize data layers (SQL/NoSQL, Prisma, TypeORM) Write unit, integration, and E2E tests (Jest, Playwright/Cypress) with meaningful coverage Debug, profile, and optimize back-end performance; monitor latency and throughput Collaborate closely with front-end developers to ensure efficient data exchange and DX Review pull requests, improve CI/CD pipelines, and mentor peers Ensure code meets accessibility, reliability, and observability standardsWhat we offerMedical and health insurance,Multisport and other lifestyle benefits,Language courses,Friendly coworkers & team spirit,Multiple geographies and clients,Work for well-known brands,Exposure to trailblazing business and technology projects,A place in the first line of a digital transformation,Everyday opportunities to influence how and where we do our business,Build a flagship mobile experience for a once-in-a-generation global event,Work with top experts across product, design, and engineering- with modern tooling and real ownership,A culture that prizes clarity, craftsmanship, and momentum; hybrid work with meaningful in-person collaboration.About DeloitteIn Deloitte we support leading global organizations in optimizing and transforming their organizations. This also relates to their finance function. Our consultants offer insights, capabilities, and solutions that change the way these organizations operate and make people-related decisions.We are currently building in Poland a dedicated team which will focus on advisory in the area of Finance & Performance. The Team will advise our Clients in complex issues relating to i.a. Reporting, Budgeting, Controlling processes. We are looking for high-energy, committed and ambitious people to join our advisory practice. Next to advising on most sophisticated and challenging issues relating to the above mentioned areas, our Consulting professionals will also advise on potential solutions leading to optimisation of the above mentioned processes. This will also include applying the newest technologies.Are you ready to join our team and help our clients imagine, deliver, and run their future?