Senior Full Stack .NET Developer / Principal Backend Engineer

Senior Full Stack .NET Developer / Principal Backend Engineer Location: Seattle, WA Position Type: Full-Time hybrid $180-200k+ + benefits Overview This role serves as a senior technical leader responsible for driving backend architecture, guiding engineering best practices, and contributing across the full technology stack.

The position focuses heavily on backend systems built with C# and .NET, while also supporting front-end integration efforts when needed. The engineer in this role will help shape the architectural vision, elevate engineering quality, and provide technical mentorship to the broader team.

Key Responsibilities

Backend & Full-Stack Development Design, develop, and maintain backend applications using C#, .NET Framework, .NET Core, and .NET 8 . Build and optimize REST APIs , including API versioning and BFF (Backend-for-Frontend) patterns. Lead data modeling and work extensively with SQL Server , including stored procedures, performance tuning, and Dapper (repository/unit-of-work patterns).

Modernize or translate existing WPF components where needed. Implement secure authentication flows such as OAuth2 and Open. Iddict , including support for server-to-server interactions. Collaborate closely with front-end engineers to ensure seamless React/TypeScript integration. Architecture & Technical Leadership Drive the architectural direction across products, ensuring scalability, reliability, and maintainability.

Set and uphold high standards for engineering hygiene, code quality, and design practices. Mentor senior and junior engineers, providing guidance in system design, coding practices, and problem-solving. Translate complex technical topics into clear communication for both technical and non-technical stakeholders. Identify, advocate for, and drive “delighter” features and improvements that enhance customer value.

Cloud, DevOps & Infrastructure Lead the design and operation of large-scale cloud services using AWS (EC2 and related services) or other major public cloud platforms. Apply DevOps and security best practices across development and deployment workflows. Utilize containerization and orchestration technologies such as Docker and Kubernetes .

Contribute to evolving infrastructure that supports data workflows and emerging AI-related systems. Cross-Functional Collaboration Partner with product, data, and engineering teams to shape technical strategies and deliver high-impact initiatives. Understand user needs and customer workflows to inform system improvements and product direction.

Operate effectively in a fast-paced environment with high ambiguity, balancing technical and business priorities.

Requirements

Required Qualifications Bachelor’s degree in Computer Science or a related field. 12+ years of experience building and operating large-scale cloud services or distributed systems. Expert-level proficiency in C# and the .NET ecosystem (.NET Framework, .NET Core, .NET 8). Strong experience with: SQL Server , relational databases, and performance optimization REST API design Dapper ORM OAuth2, Open.

Iddict, and modern authentication patterns Demonstrated experience with at least one major cloud provider (AWS, Azure, or GCP). Proficiency in at least one additional programming language (Java, TypeScript/JavaScript, Golang, Python, etc.) Experience with Docker , Kubernetes , or other container orchestration systems.

Ability to work directly with end users or customers to understand requirements and user journeys. Strong communication skills with the ability to clearly articulate technical decisions and trade-offs. Proven track record of developing technical strategies and executing them successfully. Ability to raise the engineering bar for quality, reliability, security, and maintainability.

Demonstrated success collaborating across teams and driving complex cross-functional initiatives. Nice-to-Have Qualifications Strong front-end experience with React and modern TypeScript frameworks. Experience supporting or architecting infrastructure for AI pipelines . Familiarity with NoSQL technologies, message queues, or event-driven architectures.

Experience with WPF modernization or transition to web-based UI frameworks.

Benefits

Benefits

Competitive salary ($180-200+k) and performance-based bonus opportunities Comprehensive health, dental, and vision coverage Retirement plan options Generous paid time off and holiday schedule Professional development and continuing education support Flexible work arrangements where applicable