Top Senior C# Jobs in Philadelphia, PA

Deploys, integrates, hardens, and operates modular C-UAS data and software platforms in secure DoD environments. Builds data pipelines across classification boundaries and disconnected conditions, integrates mission systems, manages Kubernetes-based infrastructure, supports accreditation, and handles observability, incident response, upgrades, and backup recovery. The role also documents solutions, trains mission teams, represents field needs to engineering, and mentors junior forward-deployed data engineers. Most work is remote with occasional travel to restricted environments and SCIFs.

Build and support complex features across C#/.NET back-end services and React front ends. Responsibilities include technical design, API and data modeling, secure and tested coding, production troubleshooting, code reviews, mentoring, documentation, and improving engineering practices. Collaborate with Product, QA, DevOps, Technical Leads, and architecture teams while balancing delivery, maintainability, performance, accessibility, observability, and security.

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.

Build and lead high-performance browser features in modern C++ and Chromium, including tracker blocking, subscription integrations, and responsiveness monitoring. Own complex projects from proposal through post-mortem, solve ambiguous technical problems, make architecture decisions, collaborate asynchronously with product and design, and use metrics to evaluate outcomes in a large-scale consumer codebase.

Build and maintain scalable, cloud-native APIs and high-value core system components using .NET and related technologies. Lead software architecture and testing discussions, enhance core offerings, collaborate cross-functionally, and ensure quality through code reviews, unit testing, functional testing, telemetry, and performance tuning. Mentor teammates and contribute to continuous technical and process improvement.

Develop and enhance software in C++ on Linux, create analytical tools for financial data, and collaborate with research analysts.

Develop software and enhance systems in C++ on Linux, while collaborating with analysts and engineers to create data processing tools.

Leads instrumentation and controls engineering design for small to medium projects, including programming, planning, detailed design, construction documentation, and administration. Develops automation control systems with controllers, HMIs, workstations, and servers; manages discipline budgets, coordinates clients and project partners, leads quality reviews, supports proposals, performs field surveys, writes specifications, and mentors junior engineers.

Design and develop low-latency, high-throughput distributed database kernels for massively parallel analytics. Responsibilities include architecture, modern C++ development, MPI/OpenMP query execution, SIMD and hardware optimization, distributed networking, database internals, in-database machine learning, vector indexing, performance tuning, code reviews, mentoring, and resolving scalability issues across large-scale clustered systems.

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.

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.

You will develop and maintain components of the LLVM based toolchain, collaborating with the community while ensuring platform-specific optimizations and tests.

Develop and maintain C++ UI applications on UNIX; apply OOP design, database knowledge, and security concepts (SSO, XSS, SQL injection). Lead small teams, work flexible hours, and communicate technical solutions.

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.