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
