Senior Fullstack Developer

Build a modern web and mobile product for the fitness industry from scratch — from architecture and code to deployment in the App Store and Google Play.

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

Apply now

18000-21000 PLN net + VAT

B2B

Remote

What will you do?

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 Claude Code, GitHub Copilot, ChatGPT, or the OpenAI API to boost productivity without sacrificing quality.
Support deployments: Collaborate on infrastructure configuration, documentation, testing, and mobile app publishing.

‍

What do we expect from you?

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, Service Bus, 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., Claude Code, GitHub Copilot, ChatGPT, or 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 skills

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.

‍

What can you expect in return?

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.

‍