Senior Full Stack .NET Developer (Ref IN051)

We’re seeking a Senior Full Stack .NET Developer to join our team and help build scalable, high-performance web applications and APIs that empower thousands of product sellers worldwide. You’ll work across the full stack, from backend services to frontend interfaces, ensuring reliability, quality, and long-term scalability in a fast-evolving SaaS environment.

About the ProjectYou’ll join a global software team developing a market-leading inventory management platform that supports merchants in selling, tracking, and optimizing products across multiple online and offline channels. The platform processes millions of orders per year and integrates with a wide ecosystem of e-commerce, retail, and logistics partners to simplify complex supply chain operations. This role requires a small overlap with U.S. working hours for collaboration with the client’s team.

Key Responsibilities:

• Design, build, and maintain web applications and RESTful APIs using C#, .NET Framework, JavaScript, and SQL Server;

• Collaborate closely with product managers, QA engineers, and developers to translate business needs into reliable, scalable solutions;

• Write clean, testable, and maintainable code aligned with modern development practices;

• Implement efficient data access using Entity Framework and optimize queries, stored procedures, and data models;

• Troubleshoot and resolve application issues, including performance bottlenecks and system bugs;

• Participate in code reviews, mentor peers, and contribute to a culture of continuous improvement;

• Work in an agile environment, proactively driving the quality and evolution of business-critical systems.

Qualifications:

• 6+ years of experience in full-stack development using .NET technologies, SQL Server, and JavaScript;

• Proven expertise with C# and .NET Framework for building modern web applications and services;

• Strong proficiency in Microsoft SQL Server and understanding of query optimization and database design;

• Experience with Entity Framework for data access and ORM;

• Familiarity with Git or similar version control systems and agile methodologies;

• Strong problem-solving mindset and a commitment to clean, maintainable architecture.

In exchange for your skills, we offer:

• Supportive relationships, built on transparency and a flat structure, in a diverse and multinational team;

• Office in the center of historical Kraków, where your dog is always welcome;

• Flexibility when it comes to working from the office or home;

• Perks include Multikafeteria, Group Life Generali insurance, Signal Iduna, Multisport, language lessons 1:1;

• Sport and other events, including weekly running, squash, and team lunches on the house;

• Free tea, coffee, and all-you-can-eat fruits and nuts in the office.

The recruitment process includes:

• HR screening 30min zoom call;

• 1h technical interview;

• General call with the team leader;

• Making an offer meeting.