Fullstack Developer

Build a modern web and mobile product for the fitness industry using .NET, React, and React Native.

You will join an interdisciplinary team delivering a comprehensive digital product for a fitness industry client. You will work alongside experienced developers and contribute to solutions used by thousands of people every day.

What You Will Do

• Develop the product end-to-end: Build and maintain backend, web, and mobile solutions.
• Build the backend in .NET: Develop secure and scalable services and REST APIs using C#, .NET 10+, ASP.NET Web API, Entity Framework Core, and SQL Server.
• Create frontend and mobile applications: Implement responsive and intuitive features using React, React Native, TypeScript, JavaScript, HTML5, and CSS3.
• Optimize data solutions: Develop business logic and improve SQL Server database structures using Entity Framework Core.
• Ensure code quality: Apply Clean Code, SOLID principles, and design patterns while writing reliable unit and integration tests.
• Leverage AI in daily work: Use tools such as GitHub Copilot, Claude Code, ChatGPT, or OpenAI API for code generation, refactoring, and workflow optimization.
• Collaborate with the team: Participate in technical discussions, code reviews, task estimation, and solution development within a distributed team.
• Create technical documentation: Document implemented solutions and collaborate with team members in both Polish and English.

What We Expect From You

• Experience: Minimum 3 years of commercial software development experience.
• Backend: Experience with C#, .NET Core / .NET 8+, ASP.NET Web API, Entity Framework Core, and SQL Server.
• Frontend & Mobile: Practical experience with React, React Native, TypeScript, JavaScript, HTML5, and CSS3.
• Quality & Best Practices: Knowledge of Clean Code, SOLID principles, and design patterns, supported by experience in unit and integration testing.
• AI & Productivity: Practical experience using AI-assisted development tools, such as Claude Code, GitHub Copilot, ChatGPT, or OpenAI API.
• Remote teamwork: Self-discipline, good work organization, and the ability to collaborate effectively in a remote team.
• Polish language: Fluent proficiency – mandatory.
• English language: Minimum B2 in speaking and writing.

Nice to Have

• Knowledge of Domain-Driven Design (DDD) and CQRS.
• Hands-on experience with microservices architecture and cloud-native solutions.
• Experience with Microsoft Azure services, such as App Services, Service Bus, Azure SQL, and Azure DevOps.
• Good understanding of Docker and containerization.
• Familiarity with Azure Cosmos DB and advanced Cloud/DevOps patterns.
• Interest in integrating AI/ML into commercial applications.
• Experience in fitness, health & wellness, or other B2C solutions.
• Experience publishing or maintaining applications in the App Store and Google Play.

What We Offer

• Compensation: 14,000–19,000 PLN net + VAT under a B2B contract.
• Paid time off: 26 fully paid days off per year.
• Remote work: 100% remote.
• Meaningful product: Work on a new digital ecosystem combining web, mobile, backend, and integrations.
• Experienced team: Collaborate with people who share their knowledge and care about quality.
• Modern technology stack: Work with .NET, React, React Native, Azure, cloud solutions, and AI tools.
• Real growth opportunities: 90% of leadership positions were filled through internal promotions.
• Autonomy and support: Take ownership of your work while receiving support from experienced team members.

Additional Benefits

• Lux Med private medical care.
• MultiSport card subsidy.
• Team integration events, birthday celebrations, and holiday gifts.