Top C# Jobs in Portland, ME

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.

As a Backend Engineer, you'll improve Git and Gitaly by contributing features, bug fixes, and performance improvements, collaborating with the open source community, and participating in architectural discussions.

Build and maintain scalable, cloud-native APIs using .NET. Enhance core platform components, lead architecture and testing discussions, optimize telemetry and performance, collaborate cross-functionally, conduct code reviews, and mentor team members.

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

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.

Remote backend C# developer to build and optimize a high-load spot-exchange matching engine. Improve performance and API throughput, implement business features, write unit and integration tests, work with .NET Core and PostgreSQL on AWS, and apply multithreading, async, and distributed systems concepts.

The Senior Software Engineer will develop and maintain client-side applications, improve installation workflows, and ensure enterprise deployment support for cybersecurity products.

Lead technical direction for a major product domain, reduce architectural debt, mentor engineers, standardize AI-agent workflows, and design scalable backend solutions integrating LLMs and cloud services. Drive cross-team RFCs, cookbook standards, and adopt agentic AI tooling while balancing security, quality, and delivery.

Perform civil/structural engineering and design tasks for power plant upgrades and new projects under senior supervision. Assist with calculations, modifications, equipment walkdowns, and design changes to improve plant performance, safety, and reliability. Work involves field and office duties, travel to client sites, and maintaining unescorted nuclear plant access.

The Senior C# Developer will lead AI enablement by transforming APIs into an Agent Mesh using C# and the MCP, ensuring secure AI interactions through Gravitee management.

Design, build, and maintain backend workflow orchestration and analyzer integrations for the ECL platform. Manage analyzer state transitions, runtime event handling, and legacy modernization; extract shared .NET libraries, collaborate with integration and QA, and support knowledge transfer.

Develop and maintain .NET Core trading systems for Linux with service-oriented architecture and multi-threaded processing. Implement async, lock-free structures and distributed systems, write unit and integration tests, optimize SQL queries, design data structures and algorithms, and work with communication protocols (SignalR, gRPC, HTTP). Use PostgreSQL, Docker, and AWS in the deployment stack.

Contribute to and optimize the performance of ClickHouse, assist with debugging, collaborate with teams, and engage with the open-source community.

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.

The Back End Software Engineer will design and build scalable services for a SaaS platform, collaborate with teams, and contribute to quality code and architecture discussions.

Design high-performance C++ libraries for automated PCB design challenges, mentoring peers and shaping technical direction while collaborating with experts in various fields.

Develop a quest gameplay engine for game server and mobile apps and build a visual no-code quest editor. Collaborate in one-week Scrum sprints, design software architecture, and use C++/Qt, JavaScript/TypeScript, git, and Linux.

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 and maintain mobile app and no-code quest editor, implement gameplay engine and server, design software architecture, and collaborate in one-week Scrum sprints using C++, Qt, QML, MySQL, and AI-assisted tools.