Top Senior C# Jobs

Develop and maintain sports trading and tools applications and platforms using .NET, C#, and SQL Server. Build scalable, low-latency, highly available software handling high-volume real-time data. Support existing 24/7 trading systems, perform root-cause analysis, collaborate with product owners and testing teams, contribute to solution proposals and estimates, and mentor technical team members. The role will also expand into Golang, React, and Google Cloud Platform.

Design and build data-driven advertising software features, scale distributed applications and infrastructure, optimize algorithms and architectures, reduce cloud costs, and improve observability. Participate in on-call rotations and incident escalation, create technical documentation and playbooks, and collaborate with distributed teams across time zones. The role requires strong software architecture, performance optimization, data modeling, Linux, and compiled-language expertise.

Design and implement high-performance datapath features for load balancing, firewall rules, and Layer 7 protocols. Build scalable networking and security systems using C or C++, data structures, algorithms, and Unix/Linux optimization. Own architectural projects from conception through large-scale deployment while applying advanced knowledge of DNS, HTTP, TCP/IP, and SSL/TLS. Use AI tools to improve engineering workflows and problem-solving.

Lead design, implementation, testing, and support of FreeWheel's high-scale video advertising platform. Own feature lifecycle, produce technical specs, write efficient code, integrate components, and maintain documentation. Provide production support, mentor junior engineers, collaborate with product and operations, and drive technical innovation and architectural decisions.

Design, customize, and maintain C++ applications in a Linux environment. Lead releases, collaborate with stakeholders and QA, mentor junior engineers, manage documentation, track performance metrics, and participate in design and peer-programming sessions. May work variable schedules including nights and weekends.

Design, build, and scale low-latency ad-serving systems and data/model-driven features. Optimize algorithms and architectures for performance and cloud cost, extend observability, participate in on-call rotations, and produce runbooks and documentation.

The Market Data Engineer will design and implement high-performance market data systems, focusing on trading infrastructure, performance optimization, and system resiliency.

Leads development of secure, scalable, high-performance, low-latency trading applications and user interfaces for global trading desks. Designs, codes, tests, reviews, debugs, and improves software across the SDLC. Drives adoption of responsible AI-assisted engineering practices, automates recurring remediation, evaluates vendor technologies, and mentors teams on secure, resilient delivery.

Lead architecture and implementation of high-performance C++ and Python systems, integrate distributed and real-time systems, own CI/CD and build tooling, debug multi-threaded systems, guide cross-team integration and mentor engineers, and evaluate new technologies to improve simulation and autonomy platforms.

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.

Lead architecture and implementation of high-performance C++ and Python systems, integrate distributed systems and hardware/software, manage CI/CD pipelines, debug and optimize real-time multi-threaded systems, guide end-to-end integration and verification, mentor engineers, and evaluate new technologies to improve system performance.

Leads software engineering projects for a global index business platform within investment banking. Develops, tests, reviews, and debugs secure Python and TypeScript production code on the Athena trading and risk platform. Collaborates with quantitative research, trading, sales, structuring, and operations teams to deliver business solutions. Drives responsible adoption and governance of AI-assisted engineering tools, improves SDLC automation, influences platform design, and serves as a technical subject matter expert.

Lead design and delivery of ultra-low-latency electronic trading systems (Smart Order Router, Matching Engine, Market Access, Risk Management). Develop and enhance trading strategies, ensure scalability and reliability, conduct code reviews and testing, and collaborate with cross-functional teams following Agile practices.

Lead engineering role building and evolving the Sigma data-visualization platform: develop C++/Rust->WASM engine, integrate Apache Arrow, build TypeScript/React (Next.js) front-end, extend data adapters, tune WASM performance, ensure secure high-quality production code, drive architecture decisions, evaluate vendors, and lead engineering communities to improve operational stability.

Lead technical design and deliver secure, scalable C#/.NET software for trading systems. Drive architecture, coding, code review, automation, resiliency, CI/CD, and adoption of AI-assisted engineering practices while mentoring teams and engaging vendors.

Design, develop, and support reusable components, interactions, frameworks and SDKs for Spectacles AR glasses and SnapOS. Contribute to OS components, participate in code and design reviews, and collaborate with design, engineering, and product teams to launch performant, test-covered features.

Lead development and design for global credit-card authorization systems. Create technical designs, implement complex features in C, write C++ unit tests (Google Test), define interfaces, improve CI/CD and development processes, lead code reviews, mentor junior engineers, and collaborate with product and other technical leads.

Design, implement, and support low-latency exchange connectivity components including market data handlers, order gateways, and reference data processors. Build APIs (REST/WebSocket/event bus), collaborate with OMS/FCM/infrastructure teams, and optimize for high throughput, fault tolerance, and observability in production trading systems.

Lead development of core client systems and engine-level infrastructure in Unity/C#. Diagnose and fix cross-cutting performance issues, upgrade third-party SDKs, evolve build tooling, produce design docs, scope multi-week infrastructure initiatives, mentor engineers, and drive profiling, optimization, and architecture changes to enable future features.

Design and implement high-performance GPU-accelerated software using C++ and CUDA. Develop CUDA kernels for signal and image processing, profile and optimize GPU applications, integrate with hardware (FPGAs, SoCs), collaborate with cross-functional teams, and apply DevSecOps/CI-CD practices to deliver production-quality defense systems.

Design, build, and maintain internal web applications for performance capture; define technical roadmaps; collaborate with Production and cross-functional teams; mentor engineers; contribute to websites, APIs, and databases; ensure reliability, maintainability, and performance.

Develop and optimize high-throughput C++ algorithms for remote sensor data exploitation, image analysis, detection, and tracking. Design software architecture, work with databases and Linux systems, contribute to Agile teams and shared tools, and apply multithreading, concurrency, data structures, and performance optimization expertise.

Design, own, and optimize low-latency trading infrastructure supporting real-time data processing, order execution, market data, and strategy implementation. Build fault-tolerant systems, execution logic, venue gateways, test harnesses, and data-analysis pipelines. Partner with quantitative researchers and traders while making architectural decisions, applying modern C++ practices, and supporting systems from design through production. The role requires onsite collaboration four days per week.

Design, implement, test, and modernize backend services and integrations (TypeScript/Node.js and C++). Lead large projects, write technical specifications and API contracts, enforce coding standards, coach engineers, and drive legacy-to-modern migrations within online banking and core systems.

Develop and maintain legacy systems while building a consolidated replacement system in a SAFe Agile environment. Design, code, debug, and implement mission-critical software using C#, AWS, Java, JavaScript, and web technologies. Create complete front-end and back-end solutions, enhance existing applications, test components, and solve complex problems collaboratively. Experience with microservices, distributed systems, cloud platforms, and additional programming technologies is preferred.