Top Senior C# Jobs in Chicago, IL

Leads complex software optimization initiatives from design through implementation and validation. Builds cloud-native services, data pipelines, dashboards, automation, and AI-enabled forecasting solutions. Analyzes cloud costs, resource utilization, reliability, capacity, and engineering productivity while partnering with Engineering, Finance, Product, Data, Platform, and SRE teams. Ensures scalable and secure integrations, testing, observability, financial data quality, and measurable savings. Provides technical leadership and mentorship to junior engineers without direct people-management responsibilities.

Design, develop, optimize, deploy, and maintain high-performance market data and automated trading systems. Process raw market data feeds, implement CME and Cboe exchange protocols, and optimize concurrency, throughput, scalability, and ultra-low-latency performance. Collaborate with traders, quantitative researchers, analysts, and engineers while supporting critical applications, automated testing, peer reviews, and best practices. Coach junior engineers and take ownership of projects from design through maintenance.

Develop cross-platform C++ and Qt software for network device discovery, monitoring, and data collection across Windows and Linux. Build high-performance, concurrent, asynchronous systems that communicate with thousands of devices using SNMP, SSH, ICMP, WMI, and related protocols. Own testing, troubleshoot issues across application, operating-system, and network layers, optimize reliability and performance, and collaborate with backend, UI, QA, and product teams.

Build and optimize low-latency C++ systems for market data processing, exchange connectivity, and order execution. Analyze performance across application, memory, CPU, networking, and operating-system layers. Collaborate with traders, FPGA engineers, and infrastructure teams, while owning production systems through design, testing, deployment, and real-time support.

Design, develop, and maintain high-performance C++ trading platform applications. Partner with traders and quantitative researchers to translate business needs into efficient technical solutions. Lead profiling, performance optimization, testing, code review, and release improvements while owning features from design through production support.

Develop scalable C++ software that defines and enforces endpoint behavior across millions of managed Windows endpoints. Responsibilities include implementing features, improving platform performance, shipping production code, designing new systems, writing architecture documents, defining subsystem contracts, and collaborating with server, UI, product, and design teams. The role requires deep Windows systems and kernel-driver expertise, with preferred experience in WHQL, minifilter or WFP drivers, macOS Endpoint Security, and Linux kernel development.

Build software, data pipelines, dashboards, and automation for cloud cost visibility, infrastructure efficiency, reliability, engineering productivity, and financial accountability. Analyze workloads and billing data, implement AI- and analytics-enabled forecasting and anomaly detection, develop cloud-native services, and support capacity planning, cost allocation, and optimization. Collaborate with Engineering, Finance, Data, Platform, SRE, Architecture, and Product teams while testing, troubleshooting, documenting, and communicating recommendations and business value.

Design, develop, test, and maintain scalable C#/.NET applications and RESTful APIs. Build data-driven platforms, implement CI/CD and DevOps practices, deploy containerized apps (Docker/Kubernetes) on AWS, troubleshoot production issues, and collaborate on architecture, code reviews, and observability improvements.

Design and develop scalable C++ software for endpoint state and control across Windows, macOS, and potentially Linux. Build reliable, multi-process systems that enforce endpoint behavior, manage local state, support IPC, and operate across millions of devices. Responsibilities include implementing features, improving platform performance, writing design documents, defining architecture and IPC contracts, and making technical decisions in an evolving, sparsely documented environment.

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 complex, scalable public safety software using C#, Angular, databases, APIs, cloud infrastructure, and AI integrations. Lead design and code reviews, guide developers, contribute to architecture, improve frameworks, address technical debt, create automated testing strategies, optimize database and application performance, and diagnose escalated production issues. Serve as a technical subject matter expert while coordinating with internal teams, customers, and external entities.

Leads and develops a software engineering team while contributing hands-on to enterprise application design, coding, testing, code reviews, production support, and technical decisions. Builds scalable solutions using C#, ASP.NET, SQL Server, and modern web technologies; partners with product and business stakeholders; supports Agile delivery, CI/CD, troubleshooting, root cause analysis, and engineering best practices. The role also includes mentoring engineers, monitoring delivery and operational metrics, and driving continuous improvement.

Design, develop, and support high-performance C++ and Python back-office post-trade processing applications. Build scalable reconciliation workflows, optimize SQL and database performance, implement monitoring and automated testing, troubleshoot production issues, and contribute to architecture and code reviews. Collaborate with technical and business stakeholders, use AI-assisted development tools, mentor junior engineers, and support reliable financial systems.

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.

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.

Leads hands-on full-stack development across architecture, implementation, testing, deployment, and support. Designs secure, scalable C#/.NET and Angular applications, cloud integrations, APIs, and data solutions on AWS. Guides developers, establishes engineering standards, manages CI/CD and automated testing, troubleshoots complex issues, and drives cloud optimization, security, and technical debt reduction. Collaborates with product, architecture, DevOps, analytics, and project teams while supporting migration of on-premises applications to AWS.

Lead a development team while remaining hands-on in full-stack engineering. Design, build, test, deploy, and support secure web applications using C#/.NET, Angular, databases, and AWS. Drive cloud migrations, architecture, CI/CD automation, application security, troubleshooting, performance and cost optimization. Mentor developers, establish engineering standards, lead technical delivery, and collaborate with product, data, DevOps, and architecture teams.

Lead end-to-end development of secure, scalable web applications and data solutions supporting clinical trial operations. Design frontend and backend components using C#/.NET, Angular, AWS, and relational or non-relational databases. Guide architecture, testing, deployment, CI/CD, security, cloud optimization, and regulatory compliance. Mentor developers, oversee technical delivery, troubleshoot complex issues, and lead migration and modernization of on-premises applications to AWS.

Build and optimize high-performance C/C++ and Rust server applications and feed handlers for market data. Implement parsers, petabyte-scale processing tools, and low-latency, high-throughput optimizations. Collaborate on build/deploy/CI, monitoring, and ensure reliable feature rollouts.

Develop high-performance, low-latency trading systems for options market making, collaborating with traders and quants to enhance performance and trading infrastructure.

As a Senior Engineer on the Market Data team, you will design high-performance libraries for trading systems, ensuring fast and reliable market data delivery while collaborating with various teams.

The role involves developing applications using .Net and SharePoint technologies, requiring a strong background in web application development and multiple programming languages.

The position involves building and optimizing automated trading infrastructure, developing trading algorithms, and creating scalable applications in a team environment.

Design and develop low-latency, high-throughput distributed database kernels for massively parallel analytics. Responsibilities include query execution, columnar storage, transaction management, cluster coordination, hardware-aware optimization, SIMD vectorization, RDMA networking, in-database machine learning, vector indexing, performance tuning, architecture reviews, code reviews, mentoring, and resolving scalability issues.

Design, build, and maintain high-throughput, low-latency C++ systems for symbol resolution. Develop scalable APIs, participate in design/code reviews, monitor and troubleshoot production, champion best practices, and mentor teammates.