Top C# Jobs in Denver & Boulder, CO

Develops and maintains .NET applications using C#, Microsoft SQL Server, unit and integration testing. Responsibilities include building features, fixing bugs, debugging across the application stack, making maintainability and performance decisions, researching solutions, communicating design choices, and collaborating with engineering peers. The role requires approximately 2–3 years of C# and MSSQL experience, Agile development experience, and a bachelor's degree or equivalent practical experience.

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.

Develop and maintain PLM and digital engineering applications using C# and .NET. Lead software design, requirements gathering, SDLC planning, coding, testing, code reviews, and technical problem-solving. Collaborate with engineers, business analysts, architects, administrators, and business representatives to deliver application solutions. Improve development quality through automated testing, peer reviews, and development standards while mentoring and guiding team members.

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.

As a Sr. Software Engineer at Bloomerang, you will lead technical direction, mentor engineers, and enhance SaaS solutions while utilizing .NET and AI tools. You will ensure scalable, maintainable applications, advocate for Agile workflows, and focus on quality outcomes in software development.

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.

Build and scale low-latency ad-serving software handling billions of daily auctions. Responsibilities include developing data- and model-driven features, optimizing algorithms and architectures, reducing cloud costs, extending observability, supporting distributed infrastructure, participating in on-call rotations, and documenting systems and incident procedures.

Develop and maintain sports trading and tools applications and platforms using .NET, C#, and SQL Server. Build scalable, low-latency, highly available software handling high-volume real-time data. Support existing 24/7 trading systems, perform root-cause analysis, collaborate with product owners and testing teams, contribute to solution proposals and estimates, and mentor technical team members. The role will also expand into Golang, React, and Google Cloud Platform.

Lead maintenance and expansion of a flagship Windows client-server accounting product. Design, implement, test, and document features; maintain large legacy C++ codebase while developing in C#/.NET. Collaborate with cross-functional teams, gather user requirements, optimize databases, ensure code quality, and apply finance domain knowledge to deliver reliable accounting software.

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.

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.

Build and validate reinforcement-learning tasks for AI agents exploring unfamiliar C repositories. Responsibilities include investigating runtime behavior, rewriting engineering questions, refining rubrics and foils, running validation workflows, documenting solutions, and addressing expert review. Work focuses on production systems such as PostgreSQL, Redis, OpenSSH, OpenSSL, and other foundational C codebases.

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.

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.

Design, develop, implement, and analyze technical products. Conduct engineering evaluations and improve product quality. Requires a bachelor's degree and 6 years of experience.

Lead a development team focused on data processing and statistical analysis, ensuring high-quality software development and complex report packaging for clients.

The C# Developer, Analyst will implement and customize software, troubleshoot issues, and engage with clients, balancing coding and business interactions.

Seeking a C# / MVC Developer to convert a VB.NET site to C# / MVC. Responsibilities include full stack .NET development, SQL development, and testing.

The Sr. C# Developer will work in an Agile/Scrum environment focusing on .NET development, rich UI web applications, and commercial software.

Seeking a C# Engineer, Architect to join a team, focusing on development and providing a technology roadmap. Requires strong architecture skills.

The C# Engineer will perform full life cycle development in an Agile environment, focusing on C# with potential work in Java, C++, and JavaScript on various projects.

The C# Developer will be responsible for developing enterprise applications, focusing on .Net/C#/SQL web application development, within a small team.