Top Senior C# Jobs in St. Louis, MO

Design, develop, and field high-performance Ground Control Station and C2 software using C++/Qt/QML and QGroundControl. Lead architecture and technical direction, mentor engineers, define APIs/ICDs, debug integration/latency issues, support field tests, implement post-mission debrief tools, and ensure interoperability with C2 standards.

The Senior Programmer Analyst will develop systems, code and document programs, assist with system design, and improve IT processes and techniques.

Contribute to high-performance, real-time applications processing critical financial data. Collaborate with teams, develop clean applications, and maintain testing strategies.

Lead and implement observability strategy for Real‑Time Collections, perform hands‑on low‑latency C++ work, embed observability practices across SDLC, define SLIs/SLOs and dashboards, establish GitOps/API-driven observability workflows, and influence platform architecture and reliability.

Design high-performance C++ libraries for automated PCB design challenges, mentoring peers and shaping technical direction while collaborating with experts in various fields.

Build and maintain scalable, cloud-native APIs using .NET. Enhance core platform components, lead architecture and testing discussions, optimize telemetry and performance, collaborate cross-functionally, conduct code reviews, and mentor team members.

You will develop and maintain components of the LLVM based toolchain, collaborating with the community while ensuring platform-specific optimizations and tests.

Develop user interface components for ArcGIS Pro using C# and WPF, work in an agile team, and design software solutions for raster and imagery processing.

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

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.

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.

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.