Top C# Jobs in Seattle, WA

Lead C++ developer to port a large compiler/interpreter codebase from x86 to x64, integrate with Office products, review and refactor code, implement high-quality unit-tested fixes, collaborate with US/India teams, and drive technical solutions and tooling improvements.

The Senior Software Engineer will develop and maintain client-side applications, improve installation workflows, and ensure enterprise deployment support for cybersecurity products.

Lead technical direction for a major product domain, reduce architectural debt, mentor engineers, standardize AI-agent workflows, and design scalable backend solutions integrating LLMs and cloud services. Drive cross-team RFCs, cookbook standards, and adopt agentic AI tooling while balancing security, quality, and delivery.

Lead C# .NET Backend Developer to architect, build, and maintain scalable microservices and RESTful APIs using .NET Core. Drive CI/CD, containerization (Docker), Kubernetes orchestration, and Azure deployments. Mentor developers, ensure code quality and security, collaborate with QA and product teams, and champion agile practices.

The Senior C# Developer will lead AI enablement by transforming APIs into an Agent Mesh using C# and the MCP, ensuring secure AI interactions through Gravitee management.

Looking for mid to senior level .NET/C# developers with SharePoint experience to enhance customer experience through new functionality. Candidates will document business requirements and develop application design documentation.

Develop and maintain .NET Core trading systems for Linux with service-oriented architecture and multi-threaded processing. Implement async, lock-free structures and distributed systems, write unit and integration tests, optimize SQL queries, design data structures and algorithms, and work with communication protocols (SignalR, gRPC, HTTP). Use PostgreSQL, Docker, and AWS in the deployment stack.

Contribute to and optimize the performance of ClickHouse, assist with debugging, collaborate with teams, and engage with the open-source community.

Develop and optimize ultra-low-latency, high-performance trading infrastructure in modern C++. Implement and tune order execution, market data connectivity, multi-threaded systems, and risk modules. Profile and benchmark real-time systems, collaborate with quants and traders, and maintain robust, fault-tolerant continuous trading operations.

The Back End Software Engineer will design and build scalable services for a SaaS platform, collaborate with teams, and contribute to quality code and architecture discussions.

Develop a quest gameplay engine for game server and mobile apps and build a visual no-code quest editor. Collaborate in one-week Scrum sprints, design software architecture, and use C++/Qt, JavaScript/TypeScript, git, and Linux.

Develop and maintain mobile app and no-code quest editor, implement gameplay engine and server, design software architecture, and collaborate in one-week Scrum sprints using C++, Qt, QML, MySQL, and AI-assisted tools.