Top C# Jobs

Develop and integrate software for Naval weapon and sensor systems, including submarine-launched ballistic missile applications. Responsibilities include requirements, architecture, development, testing, deployment, and sustainment using C/C++, Java, or Python. The role applies Agile, Scrum, DevSecOps, Git, Jira, and static analysis practices while collaborating with government and industry teams. Candidates will support software and systems engineering efforts, communicate with customers, and may work with embedded systems, GNC algorithms, and high-, low-, or medium-fidelity simulators.

Design, build, and support scalable cloud-native APIs and services in C#/.NET on Azure. Modernize desktop apps into distributed services, implement CI/CD, automated testing, observability, and mentor engineering team members while participating in Agile development and architecture reviews.

Design and implement scalable backend services, APIs, data access layers, and enterprise integrations. Write clean, tested, maintainable code using technologies such as C#/.NET, TypeScript/Node.js, and Next.js. Collaborate with frontend, DevOps, and senior engineers on end-to-end features, contribute to code reviews and documentation, and apply sound software design practices. The role may also support AI-powered applications and integrations with cloud, SaaS, and containerized environments.

Design, build, and maintain high-throughput backend services and APIs for FactSet’s Investment Book of Record platform using C# and .NET Core. Develop Python-based data pipelines, reconciliation tools, and analytics scripts; manage MongoDB and MySQL performance and integrity; contribute to architecture and code reviews; collaborate with product managers; and mentor junior engineers.

Leads the architecture, development, and delivery of a global equity derivatives pricing platform and RFQ workflow. Develops Java server and C# client features, designs REST-based solutions, maintains automated test suites, improves CI/CD pipelines, and supports deployment strategies. The role includes requirements refinement, architecture planning, proof-of-concepts, agile delivery, compliance, mentoring engineers, and collaboration with business and platform partners.

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

As a Full Stack Engineer, you'll develop online services features using C#, React, and ensure best practices in software development. Collaboration with global teams is key.

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

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.

Develop and modernize enterprise applications using C#/.NET and PostgreSQL, including refactoring a Microsoft Access/VBA application. Responsibilities include writing maintainable code, participating in code reviews, testing, documentation, deployment, and collaborating with the software development team in a fully remote environment.

Develop and maintain scalable enterprise web applications using React, JavaScript or TypeScript, C#, and .NET. Build responsive interfaces, backend services, REST APIs, and microservice integrations. Design Azure cloud solutions, support CI/CD deployments, participate in architecture and code reviews, troubleshoot applications, and collaborate with stakeholders, QA, product owners, and developers in an Agile/Scrum environment.

Design, build, and maintain data pipelines, datasets, APIs, storage systems, and research infrastructure supporting quantitative trading. Develop big data tooling for cluster and high-throughput computing, improve scalability and performance, manage data transmission between C++ and Python, and support releases, debugging, maintenance, and storage expansion. The role also involves leading technical projects and mentoring junior engineers.

Design, build, and maintain Stellar Core, the distributed system powering the Stellar blockchain. Responsibilities include developing scalable network components, improving peer-to-peer and processing performance, strengthening resilience and decentralization, investigating bottlenecks, authoring protocol specifications, and contributing to architecture, code reviews, and open-source engineering practices.

Design, build, and maintain Stellar Core, the distributed system powering the Stellar blockchain ledger and consensus. Develop scalable, resilient components; improve peer-to-peer networking and processing performance; investigate bottlenecks; and contribute to architecture, code reviews, RFCs, formal verification, simulations, and open-source collaboration. The role requires production C++ or Rust expertise, strong software design skills, and ownership of core subsystems.

Lead modernization of a 30-year-old Store Management System by reverse engineering EZC file-based platforms, migrating data and applications to PostgreSQL, and developing enterprise C/C++ software. Responsibilities include architecture, systems integration, APIs, ETL, performance optimization, troubleshooting, documentation, and maintaining business continuity. The role also applies AI-assisted development tools for code analysis, documentation, testing, and modernization while mentoring teams and supporting legacy and modern environments.

Designs and implements cross-platform Android and iOS features using modern C++, including Chromium browser and OpenGL ES game-engine capabilities. Integrates on-device AI, LLMs, agents, and inference technologies while optimizing latency, memory, power, and performance. Collaborates across teams, integrates APIs and SDKs, writes tests, troubleshoots issues, and improves mobile application stability and responsiveness.

Leads development, architecture, validation, integration, and documentation of C++ medical imaging software and machine-learning-enabled clinical workflows. Collaborates with product, architecture, systems, testing, and AI/ML teams to deliver Azurion and IntraSight integration features. Translates requirements into BDD scenarios, supports Agile planning, contributes to risk management and FMEA, and ensures compliance with medical-device regulations and quality processes.

Develop and support AMDOTS data collection, retrieval, processing, transmission, reporting, ETL, SQL Server databases, and C++ software. Maintain Remote Monitoring Units, interfaces, networks, operating systems, software releases, documentation, disaster recovery plans, and user support. Provide data warehouse administration, technical troubleshooting, training, and site installation support in classified DoD environments, with periodic travel required.

Build and maintain C++ backend services, workflow automation, factory software, data pipelines, databases, and machine integrations supporting digital manufacturing. Develop tools for scheduling, production execution, process data collection, and operator workflows. Own infrastructure including build systems, CI/CD, deployment, AWS resources, and developer tooling. Collaborate with manufacturing and process engineering teams to automate and scale factory operations.

Develop and test full-stack software for a real-time hospital patient monitoring platform. Responsibilities include designing scalable and reliable components, writing technical specifications, implementing software solutions, reviewing code, mentoring engineers, optimizing performance, and applying engineering best practices in an Agile environment. The role uses C#, .NET, React, GraphQL, databases, and cloud-native technologies while collaborating with cross-functional teams.

Designs, develops, tests, deploys, and supports scalable full-stack enterprise applications for Fidelity’s retirement platforms. Builds RESTful APIs and transactional systems using C#, .NET, and Java; develops cloud-neutral, containerized services; participates in architecture and code reviews; modernizes legacy systems; supports production releases; and mentors junior developers within Agile Scrum teams.

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.

Develop and sustain a high-performance geospatial collaboration and intelligence reporting tool. Responsibilities include implementing mission-driven enhancements, maintaining existing code, troubleshooting application interfaces, testing, integration, and resolving production issues. The developer will work with Java, C/C++, scripting languages, databases, search platforms, REST services, and Linux. Participation in a rotating pager schedule is required for emergency 24/7 support.

Develop and maintain large Python systems and C/C++ software supporting national security missions. Use Bash and other scripting languages, analyze RF signals, and work with embedded hardware, STM32 microcontrollers, Raspberry Pi devices, digital logic, and hardware debugging tools. The role requires a Top Secret/SCI clearance with favorable polygraph, 15 years of relevant software engineering experience, and a bachelor's degree or equivalent experience.