Principal Software Engineer (C#/.NET)

Location: Chicago, Illinois, United States of America; four days in the office

Salary: $182,325–$235,950 annually, plus potential annual incentive compensation and long-term equity participation.

Company

Financial market infrastructure and tradable-products provider delivering trading, clearing, and investment solutions.

What you will do

• Lead the architecture and implementation of C#/.NET back-end services for order execution, market data, analytics, and risk workflows.
• Own REST, gRPC, and real-time streaming API contracts, including versioning, deprecation, documentation, and backward compatibility.
• Build low-latency market-data distribution, order and execution event streams, and high-throughput messaging.
• Define microservice boundaries and standards for inter-service communication, security, observability, capacity planning, and performance.
• Partner with front-end, WPF desktop, and client-integration teams to support integrations, requirements analysis, and troubleshooting.
• Establish testing and CI/CD standards, mentor engineers, provide architectural direction, and resolve complex production issues.

Requirements

• 10+ years of hands-on back-end and distributed-systems development experience.
• Expertise in C#/.NET, ASP.NET Core, asynchronous programming, concurrency, threading, and performance optimization.
• Experience building platform-level or externally consumed APIs with REST, gRPC, WebSockets, OpenAPI/Swagger, and Protobuf.
• Strong knowledge of microservices, event-driven design, message brokers, streaming platforms, SQL, databases, testing, and CI/CD.
• Experience with authentication and authorization using OpenID Connect and OAuth 2.0, plus secure API practices.
• Candidates must be legally authorized to work in the United States without current or future employer sponsorship.

Nice to have

• Financial-industry, real-time trading, order-routing, market-data, FIX, OEMS, or venue-integration experience.
• Experience with OpenTelemetry, Prometheus, Grafana, Datadog, Docker, Kubernetes, or cloud platforms.
• Familiarity with GraphQL, WPF clients, PowerShell, Git, Jenkins, Jira, Confluence, JetBrains tools, or Wireshark.

Culture & Benefits

• Four-day in-office work model supporting team connection and collaboration.
• Opportunities for professional and personal development and internal mobility.
• Potential annual incentive compensation and participation in long-term equity programs.
• Office located in Chicago's Old Post Office district with public transportation access, restaurants, fitness facilities, and collaborative workspaces.