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

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