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