Senior Full Stack NET Developer

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 Project

You’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.