Middle Fullstack Developer (.NET + React)

co.brick talents — powered by AI, powered by people. Fullstack Developer (. NET + React / React Native)Location: 100% RemoteEngagement: Full-time (168 hours/month)About the roleOn behalf of our client, we are looking for an experienced Fullstack Developer to join their distributed team. In this role, you will be responsible for developing a product end-to-end—from building secure and scalable . NET backend services to creating responsive web and mobile applications. Our client strongly emphasizes clean architecture, high code quality, and actively leveraging modern AI tools to optimize the development workflow. What will you 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 do we expect from you? Experience: Minimum 3 years of commercial software development experience. Backend: Solid 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 (e.g., Claude Code, GitHub Copilot, ChatGPT, or OpenAI API). Remote teamwork: Self-discipline, good work organization, and the ability to collaborate effectively in a fully remote environment. Language skills: Fluent proficiency in Polish (mandatory) and minimum B2 in English (speaking and writing). Nice-to-have skillsKnowledge of Domain-Driven Design (DDD) and CQRS. Hands-on experience with microservices architecture and cloud-native solutions. Experience with Microsoft Azure services (App Services, Service Bus, Azure SQL, 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.