At Madiff, we connect top IT talent with cutting-edge companies through remote Agile teams and nearshore outsourcing. With operations in Poland, Portugal, France, and the UK, we specialize in AI, DevOps, and Cybersecurity – supporting industries like Telecom, Banking, and Hi-Tech.Are you a seasoned backend engineer passionate about building high-performance services in a cloud-native environment? Our client in the banking and smart-shopping industry is seeking a Senior .NET Developer to strengthen the platform behind a large-scale cashback and loyalty ecosystem used by millions of users.Key responsibilities Develop and enhance backend services using .NET 8 and C# Build and maintain RESTful APIs and microservices designed for high-traffic workloads Integrate backend systems with external APIs and data providers Work extensively with Azure Cloud (App Services, Azure Functions, AKS, Blob Storage, Cosmos DB) Implement unit and integration tests to ensure reliability and robustness Use Azure DevOps, Docker, and Git to support CI/CD and version control processes Cooperate closely with DevOps on optimising deployment pipelines and cloud infrastructure Contribute to code reviews, architecture discussions, and Agile ceremonies Maintain technical documentation and API specifications What we are looking for: 4–5+ years of commercial experience with C# and .NET, ideally .NET 8 Demonstrated ability to design scalable, secure REST APIs Solid understanding of Azure Cloud and distributed microservices environments Strong experience with relational databases (MS SQL Server, PostgreSQL) and ORM tools (EF Core, Dapper) Familiarity with Azure DevOps, Docker containers, Git, and modern CI/CD pipelines Knowledge of application security, error handling, and performance optimisation Experience working in Agile/Scrum teams and communicating with stakeholders Nice to have: e-commerce, cashback, or affiliate marketing background; NoSQL expertise (Cosmos DB, MongoDB); event-driven tools (Azure Event Grid, Kafka); awareness of front-end technologies What we offer Flexible working model with a remote-first approach and autonomy in your delivery (1 day/ month from Warsaw on-site) Opportunity to contribute to a large-scale, high-impact digital product with strong market presence Work within a modern .NET and Azure-based engineering ecosystem

Stable collaboration in a fintech environment that combines corporate robustness with startup agility