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.