Top C# Jobs

The role involves building and supporting production-level trading systems in C++ for credit and rates products, collaborating with traders and quantitative researchers.

Design, implement, test, and deploy high-performance C++ APIs exposing a mortgage analytics quantitative library for interest rate modeling, prepayment/default analysis, derivative valuation, hedging, and forecasting. Improve performance, reliability, and usability of the library and collaborate with business, model development, validation, and IT teams.

Design, implement, and optimize high-performance C++ APIs exposing a mortgage analytics library for interest rate modeling, prepayment/default analysis, derivative valuation, hedging, and forecasting. Collaborate with business, model development, validation, and IT; improve library performance, safety, reliability, and usability; deploy and test production code.

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.

Write and maintain efficient C++ code, support design and development of new applications, implement unit and integration tests, document processes, analyze integration needs and system architecture, collaborate with QA, troubleshoot performance issues, and work variable schedules as needed.

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 efforts across design, development, testing, troubleshooting, and operational stability. Builds secure, scalable production applications using C#/.NET, Java, React, and related technologies; reviews code and drives automation, CI/CD, cloud development, and testing practices. Leads adoption of approved AI-assisted engineering tools with responsible-use standards, evaluates architectural solutions with vendors and internal teams, and promotes engineering communities of practice.

Software Engineers at Citadel develop, maintain, and support high-performance trading platforms, focusing on custom software solutions and system stability.

Develop and enhance performance-critical C++ applications for ultra-low latency trading systems, collaborating across teams to analyze and optimize performance.

Responsibilities include developing scalable server-side features, optimizing performance, and collaborating with teams to enhance online services for games.

Develop scalable server-side features, online services, and collaborate with teams. Requires C#, .NET expertise and experience in distributed systems.

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.

Lead design, develop, test, and operate ultra-low-latency C++ trading connectivity and risk modules on Unix/Linux. Integrate FPGA pipelines with C++ for deterministic performance, automate remediation, establish latency/throughput/resiliency tests, and drive AI-assisted engineering adoption across the team.

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.

Join an on-site Chicago team building high-performance C++ trading systems. Contribute to design, development, testing, profiling, and troubleshooting. Collaborate with traders and senior engineers, receive mentorship, and gain exposure to the full lifecycle of low-latency trading platform development.

Join an on-site Chicago team building high-performance C++ trading systems. Design, develop, test, profile, and troubleshoot low-latency applications while collaborating with traders and senior engineers. Receive mentorship, training on markets, and exposure to production lifecycle and performance tuning.

Design, implement, and maintain C++ components for a global electronic trading platform. Collaborate on system design, perform code reviews, troubleshoot production issues, and improve system stability while participating across the software development lifecycle.

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.

Software Engineers at Citadel develop software solutions for trading platforms, optimizing performance and functionality, and support trading activities.

Designs, develops, tests, and troubleshoots secure, stable .NET applications. Writes high-quality C# code, works across the SDLC, uses CI/CD and AI-assisted dev tools, and collaborates within agile teams to ensure operational stability.

Lead development of a distributed, multi-asset Order Management System (OMS): design and implement core OMS infrastructure (workflow engine, pipeline, caching, event distribution), build automated deployment, improve legacy systems, ensure low-latency, high-availability, and support production stability while mentoring teams and evaluating vendor/architectural solutions.