Principal Software Engineer

Job Description:

Building trusted markets — powered by our people

At Cboe Global Markets, we inspire our people to solve complex challenges together because what we do matters. We provide the financial infrastructure that powers the global economy. As a leading provider of market infrastructure and tradable products, Cboe delivers cutting-edge trading, clearing and investment solutions to market participants around the world.

We’re building meaningful ways to support professional and personal development while strengthening the trust we’ve earned as a global market leader. Our teams are empowered to share ideas, actively pursue them and bring on a challenge. As champions of internal mobility and access to opportunity, we encourage our people to “go for it” and equip our managers with the training to coach their teams to the next level. We strive to provide employees a safe space to network, share ideas and create opportunities.

To support strong partnership and team connection, this role follows a four day in office work model.

Location Overview

Cboe HQ is located in the historic Old Post Office district, i t’ s a landmark that blends classic architecture with modern amenities. The building features expansive spaces with high ceilings and large windows, offering an abundance of natural light and panoramic views of the city skyline and the Chicago River.

With its prime location in the heart of downtown, the OPO Building provides easy access to major transportation hubs, including Union Station and multiple CTA lines, making it convenient for commuters. The building is home to a variety of amenities, including restaurants, a fitness center, and collaborative workspaces, creating a vibrant and dynamic work environment in one of Chicago's most iconic areas.

Role Overview

Cboe’s Data Vantage division — the team behind the Silexx order and execution management platform — is looking for a Principal Software Engineer to lead the design and build-out of our back-end services and API infrastructure. This is a hands-on principal role for a seasoned back-end engineer who is an expert in C#/.NET and who thinks in terms of contracts, throughput, and reliability. You will architect and implement the services, APIs, and real-time data pipelines that power Silexx’s trading, analytics, and risk-management workflows, and you will define how our own clients and our customers’ systems integrate with the platform. The ideal candidate has spent years building low-latency, high-volume distributed systems, has a deep understanding of RESTful, gRPC, and streaming transport protocols, and treats API design, versioning, and backward compatibility as first-class engineering concerns. You will be comfortable working with AI coding assistants such as Claude across the software development lifecycle to accelerate delivery and raise quality.

Your responsibilities will be:

Lead the design, architecture, and implementation of Silexx’s back-end services in C#/.NET — spanning order and execution workflows, market data, analytics, and risk.

Own the API platform end to end: define REST, gRPC, and real-time streaming contracts, establish versioning and deprecation policy, and maintain backward compatibility for the internal teams and external clients that depend on them.

Build and scale real-time data distribution — market data fan-out, order and execution event streams, and low-latency messaging — against explicit latency and throughput targets.

Define the service topology: decompose large components into well-bounded microservices, set service boundaries, and establish standards for inter-service communication.

Implement secure server communications and authentication/authorization using RESTful and streaming protocols, OpenID Connect, and OAuth 2.0.

Drive observability, capacity planning, and performance profiling for systems that must remain available through market hours, and maintain a highly available production platform.

Partner with the front-end, WPF desktop (Silexx OEMS), and client-integration teams so that the APIs you design are practical for the clients that consume them; support customers through integration, requirements analysis, and troubleshooting.

Establish back-end engineering standards — automated unit, integration, and contract testing, CI/CD release gates, code review, and API documentation.

Provide architectural direction for continued growth into new asset classes, products, regions, and models; distill complex requirements into manageable features and tasks.

Mentor engineers across teams, help managers onboard and train new associates, and act as a key participant in the interview and assessment process.

Diagnose and resolve complex production problems spanning the service, data, and network layers.

The ideal candidate has

Bachelor’s degree in Computer Science, Software Engineering, or a related STEM field.

10+ years of hands-on experience in professional back-end and distributed systems development.

Expert-level command of C#/.NET and ASP.NET Core for building high-throughput, production-critical services.

Demonstrated ownership of a platform-level or externally consumed API — design, versioning, documentation, and support of the consumers on it.

A track record of building low-latency, high-volume, highly available distributed systems.

Strong OOP skills, experience with design patterns, and a solid grounding in computer science fundamentals including data structures, algorithms, and concurrency.

Experience mentoring engineers and providing technical leadership across teams.

Experience dealing with customers through support and requirements analysis.

Back-End Development:

Advanced experience with C#/.NET and ASP.NET Core, including async/await, concurrency and threading models, and memory- and GC-aware performance work.

Microservices architecture, service decomposition, and event-driven design.

Proficiency in building RESTful APIs, gRPC services, WebSockets, and other real-time communication methods.

Expertise in throughput optimization techniques, serialization (MessagePack, Protobuf), and compression methods.

Experience with message brokers and streaming platforms such as Kafka, RabbitMQ, or Redis.

Strong understanding of data structures and algorithms, profiling, and performance optimization.

Strong SQL skills, sufficient to write and tune complex queries against production workloads.

API Platform & Integration:

Contract-first API design using OpenAPI/Swagger and Protobuf IDL, with a deliberate approach to schema evolution and versioning.

Command of API gateway concerns: routing, throttling and rate limiting, quotas, idempotency, pagination, and a consistent error model.

Experience publishing and maintaining developer-facing API documentation and client SDKs.

Networking fundamentals — TCP/IP, TLS, HTTP/2, load balancing, and connection management for long-lived streaming sessions.

Testing & Quality:

Expertise designing and implementing unit, integration, and contract test automation for services and APIs, using xUnit/NUnit and API/contract testing tooling.

Experience embedding automated tests into CI/CD pipelines as release gates.

Load, soak, and latency testing of services at realistic market-hour volumes.

Data & Persistence:

Proficient in database technologies such as Postgres, SQL Server, and MySQL, and ORM frameworks like Entity Framework.

Schema design, indexing, query tuning, and zero-downtime migrations across transactional and time-series workloads.

Security:

Expertise in implementing authentication and authorization using OpenID Connect, OAuth 2.0, and related security standards.

Secure API practices including input validation, secrets management, and least-privilege access.

Experience with security code scanning and remediating identified vulnerabilities.

Other Skills:

Proficiency using AI coding assistants su