Senior Fullstack Developer

About the Position

Senior Fullstack Developer

Senior • Remote

18,000 - 21,000 PLN/mo

Warsaw, Poland

At Qodeca, we create modern digital products for clients worldwide. We are looking for a Senior Fullstack Developer who is fluent in both .NET backend development and frontend/mobile applications based on React and React Native.

You will join an interdisciplinary team delivering a comprehensive product for a fitness industry client. You will have a real impact on technical solutions, code quality, and how thousands of users utilize the club's services on a daily basis.

The Project You Will Work On

We will design, build, test, and deploy a digital ecosystem for a fitness company, including:

• iOS and Android mobile application
• Web panel for employees
• Backend and integrations
• Complete deployment

Responsibilities

• Develop the product end-to-end: Design, build, and maintain backend, web, and mobile solutions.
• Build the backend in.NET: Develop services and REST APIs using C#,.NET 10+, ASP.NET Web API, and Entity Framework Core, working with SQL Server.
• Create frontend and mobile apps: Implement features in React, React Native, and TypeScript, ensuring a consistent user experience across web, iOS, and Android.
• Design cloud solutions: Work with microservices architecture, Azure, and Docker containerization.
• Develop integrations: Connect the system with ABC Fitness, Stripe, and communication/notification services.
• Ensure quality: Apply Clean Code, SOLID principles, and design patterns, while writing unit and integration tests.
• Co-shape the architecture: Participate in design discussions, code reviews, and technical decision-making.
• Leverage AI in daily work: Utilize tools like GitHub Copilot, and the OpenAI API to boost productivity without sacrificing quality.
• Support deployments: Collaborate on infrastructure configuration, documentation, testing, and mobile app publishing.

Requirements

• Experience: Minimum 5 years of commercial software development experience.
• Backend: Very strong knowledge of C#, .NET Core /.NET 8+, ASP.NET Web API, Entity Framework Core, and SQL Server.
• Frontend & Mobile: Hands-on experience with React, React Native, TypeScript, JavaScript, HTML5, and CSS3.
• Architecture: Practical experience with microservices and cloud-native solutions.
• Microsoft Azure: Experience with services such as App Services, Azure SQL, and Azure DevOps.
• Containerization: Good knowledge of Docker and container workflows.
• Quality & Best Practices: Solid understanding of Clean Code, SOLID principles, and design patterns, along with experience in unit and integration testing.
• AI & Productivity: Practical use of AI programming assistants, e.g., GitHub Copilot, and the OpenAI API.
• Autonomy: Strong sense of ownership, self-discipline, and the ability to work effectively in a remote team.
• Polish language: Fluent proficiency - mandatory requirement.
• English language: Minimum B2 in speaking and writing.

Nice to Have

• Familiarity with Domain-Driven Design (DDD) and CQRS.
• Knowledge of Azure 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 and maintaining apps in the App Store and Google Play.

We Offer

• Compensation: 18,000–21,000 PLN net + VAT under a B2B contract.
• Paid time off: 26 fully paid days off per year.
• Remote work: 100% remote - a model we used long before it became the standard.
• Real impact: Co-shape the architecture, technical standards, and foundations of a brand-new product.
• Experienced team: Work in an interdisciplinary environment with people who share knowledge and care about quality.
• Modern stack: Projects combining.NET, React, React Native, Azure, cloud solutions, and AI tools.
• Real growth opportunities: 90% of leadership positions at Qodeca were filled via internal promotions.
• Autonomy: Trust, space for decision-making, and ownership of results.

Additional Benefits

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

About the Company

Qodeca sp. z o.o. is a software-development and digital-product company that creates modern web and mobile solutions for clients worldwide. It works across technologies including cloud platforms, web and mobile applications, and AI-enabled development, with an emphasis on end-to-end product delivery. Its culture appears to value technical quality, clean engineering practices, knowledge sharing, autonomy, ownership, and internal growth; notably, it states that 90% of its leadership roles have been filled through internal promotion. The company operates with a remote-first model. The offer does not specify its overall headcount or formal mission statement.

Want to build a product that combines.NET, web, mobile, cloud, and AI? Apply - let's talk.