Top C# Jobs in St. Louis, MO

Lead technical design, development, certification, delivery and sustainment of C-17 pilot and maintenance training devices. Provide senior technical leadership, oversee specifications/configuration, manage risk, collaborate with engineering, program management, customers and suppliers, and contribute to proposals and SOWs.

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.

As a C++ Software Engineer, you will design and develop software solutions, ensuring performance, stability, and quality through testing and collaboration with teams.

Develop and maintain C/C++ software for telecom environments on Linux. Produce software documentation, use git/Gerrit/GitHub/GitLab, perform shell scripting and basic system administration. OpenStack experience is a plus.

The C# Developer will enhance and develop applications across various tiers, requiring strong analysis, design skills and proficiency in C# and .NET environments.

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.

The C# Developer will design, develop, and support IT solutions using various technologies, ensuring feasibility and leading project initiatives during the software development life cycle.

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

The Junior C# Developer will assist in developing system designs, coding, testing, and documenting programs under supervision, while suggesting process improvements.

As a Web Developer, you'll collaborate in a Scrum/Agile team to design and develop web applications using C#, .NET, HTML, and JavaScript, among others.

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.

Lead design and delivery of complex backend features for a high-scale online banking platform. Own code from design to production, modernize legacy systems, develop microservices, design APIs, implement tests, ensure secure coding, use AI-assisted tools, troubleshoot issues, and document APIs while collaborating with product, QA, and front-end teams.

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.

Design and implement complex low latency, high throughput software for financial data distribution, conduct testing, and improve software reliability.

Design and evaluate performance engineering tasks for AI training/evaluation. Optimize runtime, compilers, memory, CPU/GPU and concurrency. Produce documented solutions, evaluate AI-generated code, and build evaluation frameworks and scoring rubrics while collaborating with researchers and SMEs.

The C# / .NET Developer will design and maintain middleware applications, build Shopify integrations, and support a mobile app backend in a remote work environment.

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.

PrivateID seeks a Principal C++ Engineer with at least 10 years of experience to lead complex systems and scale their platform in a remote-first environment.

Remote backend C# developer to build and optimize a high-load spot-exchange matching engine. Improve performance and API throughput, implement business features, write unit and integration tests, work with .NET Core and PostgreSQL on AWS, and apply multithreading, async, and distributed systems concepts.