Regular .NET Developer (Card Payment Systems)

Job Description

• 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 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 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
• 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
• We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.
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