We are looking for an experienced Senior/ MID Fullstack .NET Developer for one of our clients. You will work on system integration projects and provide support for integration solutions. The project team includes a Technical Lead, Software Architect, QA Manager, and other Software Developers.Location: 100% Remote (Working hours: 9:00–17:00 CET)Client: US-based company with a branch in WarsawPolish language requiredContract type: B2BRate: 150–160 PLN/h + VATResponsibilities:Collaborating on business and technical requirementsMaintaining task status in Azure DevOpsSupporting the Software Architect in technical designAssisting in project planning (scope and effort estimation)Monitoring and reporting the status of assigned tasksDeveloping code according to established standards and guidelinesConducting code reviewsWriting unit testsDebugging and bug fixingMust-have:Proficiency in English and Polish (C1 level)- must have !6+ years of experience as a C#/.NET DeveloperStrong experience with REST APIsSolid knowledge of Microsoft Azure stackUnderstanding of Onion Architecture, Domain-Driven Design, and Test-Driven DevelopmentAbility to read and create technical diagramsGeneral IT knowledge (infrastructure, security)Experience with integration projects (API development and consumption, SOA, event-driven architecture)Knowledge of OAuth 2.0Familiarity with Azure Durable FunctionsExperience with JavaScript frameworks (React.js or Angular)Understanding of software and system testing principlesNice to have:Experience in AI-related projects or projects in the financial, tax, or banking sectorInterested? Don’t hesitate—apply now and join us!Would you like a version formatted for LinkedIn or job boards as well?