Top C# Jobs in Seattle, WA

Develop and support C++ features for Lens Engine and Lens Studio, enabling augmented reality experiences across Snapchat and Specs. Contribute to agentic development tooling, architecture, technical roadmaps, code reviews, and cross-functional engineering efforts. Improve code quality, reliability, performance, testing, maintainability, and developer productivity while integrating AI-assisted workflows and systems.

Design and optimize high-performance C++/CUDA libraries for GPU-based data processing. Improve multi-node GPU communication (UcxExchange), optimize Presto GPU query performance, and lead enhancements across Presto, Velox, and cuDF projects for efficient DataFrame and database acceleration.

Develop and maintain macOS systems software using modern C++, Swift, and Objective-C++. Work with process models, IPC, Endpoint Security, Network Extension, security and cryptography APIs, device and storage frameworks, packaging, deployment, and MDM tooling. Profile and debug performance using Instruments, LLDB, os_log, and os_signpost, while creating tests with XCTest, sanitizers, fuzzing, and xcodebuild CI. Support shared codebases across macOS, Windows, and Linux.

Develop and maintain cross-platform macOS systems software using modern C++, Swift, and Objective-C++. Work with IPC, daemons, system extensions, network and endpoint security, device and storage APIs, code signing, packaging, and deployment. Profile and debug performance issues, build automated tests and CI pipelines, and support Apple Silicon and Intel systems. Nice-to-have experience includes SwiftUI, AppKit, macOS beta testing, and shipping EDR, antivirus, network security, or device-management products.

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 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 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.

Designs and builds scalable, resilient distributed systems and applications using .NET, C#, microservices, REST APIs, cloud platforms, containers, and DevOps practices. Responsibilities include architecture, coding, code reviews, reusable components, monitoring, continuous delivery, infrastructure as code, cross-functional collaboration, mentoring engineers, and improving engineering processes.

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 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 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.

The role involves developing Power BI reports, dashboards, and visualizations, working with T-SQL and SSAS, and requires extensive experience in C# and ASP.Net.

The C# ETL Azure Developer will work in agile environments to develop high-performance C# libraries for Azure Data Factory, ensuring strong standards, scalability, and troubleshooting capabilities. Candidates should have strong SQL and object-oriented design skills, as well as experience with Azure cloud development.

Design, implement, and operate core networking software for a large-scale GPU datacenter fabric. Develop routing and traffic-engineering algorithms, real-time switch software, prototypes and experiments, deployment and CI tooling, monitoring, and testing to maximize performance and reliability of AI training infrastructure.

Design and develop massively parallel distributed database kernels for real-time analytics at terabyte and petabyte scale. Responsibilities include low-level C++ development, MPP query execution, SIMD and hardware optimization, distributed communication using MPI and RDMA technologies, database internals, vector indexing, in-database machine learning, performance tuning, architecture reviews, mentoring, and resolving scalability issues.

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.

The C# / .NET Developer will design and maintain middleware applications, build Shopify integrations, and support a mobile app backend in a remote work environment.

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.

PrivateID seeks a Principal C++ Engineer with at least 10 years of experience to lead complex systems and scale their platform in a remote-first environment.

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#/.NET (or Java) applications, write SQL, and work with telemetry and big-data tools (Hadoop, Pig, Hive). Leverage Microsoft technologies to deliver enterprise IT solutions.

Lead C++ developer to port a large compiler/interpreter codebase from x86 to x64, integrate with Office products, review and refactor code, implement high-quality unit-tested fixes, collaborate with US/India teams, and drive technical solutions and tooling improvements.

Design, refactor, and build high-performance C++ core infrastructure for vehicle dynamics and Starlink simulations. Lead Monte Carlo and HPC simulation development, optimize performance and reliability, create testing/HITL frameworks and visualization tools, and collaborate cross-functionally to model multi-body physics, environmental effects, and hardware behavior while improving CI, profiling, and testability.

Looking for mid to senior level .NET/C# developers with SharePoint experience to enhance customer experience through new functionality. Candidates will document business requirements and develop application design documentation.