Senior Full Stack .NET Developer / Principal Backend Engineer

Senior Full Stack .NET Developer /
Principal Backend Engineer

Location: Seattle, WA

Position Type: Full-Time hybrid

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 OpenIddict, 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, OpenIddict, 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