Regular .NET Developer (Card Payment Systems)

✨ About the Role ✨

We are looking for a Regular .NET Developer to join a team responsible for developing and maintaining core card payment systems – from transaction authorization and settlement to integrations with external payment services.

The systems process hundreds of thousands of transactions daily, so performance, availability, and security are key priorities.

Work model: Remote-first with scheduled on-site team meetings (2 days per month in Warsaw).

🚀 Responsibilities 🚀

• Develop and maintain .NET applications in the card payment domain.
• Design and implement new functionalities according to business and regulatory requirements.
• Integrate systems with external services (REST, SOAP, messaging queues).
• Optimize performance, availability, and security of applications.
• Cooperate with Analysts, Architects, and QA in Agile/Scrum teams.
• Participate in SIT/UAT testing, code reviews, and preparation of technical documentation.

💡 Required Skills 💡

• Commercial experience with C# and .NET (Framework / Core).
• Experience with ASP.NET Core, Angular, and WebAPI.
• Knowledge of Entity Framework, LINQ, Dapper.
• Experience with SQL Server (T-SQL) and query optimization.
• Knowledge of SOLID principles and design patterns.
• Experience writing unit tests (xUnit / NUnit).
• Experience with system integrations (REST, SOAP, JSON, XML).
• Experience working in an Agile environment.
• Knowledge of Git, CI/CD, and TeamCity.

🗣️ Language Requirements 🗣️

• Polish: Native or C2 level (required).
• English: Professional level enabling work with technical documentation.

🌟 Nice to Have 🌟

• Experience in card payments / payment processing domain.
• Knowledge of Docker / Kubernetes.
• Experience working on high-availability or complex distributed systems.

💰 Compensation 💰

100 zł - 110 zł an hour

🎁 Margo Offers 🎁

• B2B cooperation.
• Remote working model.
• Benefits such as medical care and sports card.
• Co-financing trainings, certification exams, and post-graduate studies.
• Ability to work in an international consulting company on ambitious projects.
• Possibility to get involved in outside-project activities with additional remuneration.
• Excellent working atmosphere, integration events.