Senior Software Engineer

(Base salary is only one part of Group One Trading's total compensation, which includes an annual discretionary bonus.)

THE OPPORTUNITY

Our Senior Software Engineers build and improve the real-time systems that power our options market-making business. They work directly with traders and other technologists to translate complex business and trading requirements into reliable production software, and take ownership of critical systems from initial design through deployment and live operation. This is a hands‑on engineering role for someone who can reason deeply about software architecture, performance, and production behavior.

THE SKILLSET

Our production environment is primarily heavily‑optimized C#, with C++ integrated into especially performance‑sensitive components. We value demonstrated engineering ability over experience with a particular language, and we embrace agentic AI workflows as a valuable asset to our engineering approach.

Our ideal Senior Software Engineer possesses the following:

• Substantial professional software development experience throughout the full software development lifecycle, including requirements analysis, architecture, implementation, testing, deployment, monitoring, and production support
• Strong software engineering instincts, treating abstraction, maintainability, testability, observability, and operational reliability as first‑class design concerns
• Experience developing real‑time, high‑throughput software for electronic trading, financial markets, or another performance‑sensitive production environment
• Ability to lead technical design discussions, make pragmatic architectural decisions, mentor other developers, and improve engineering standards across the team
• Strong written and verbal communication skills, including the ability to explain complex technical concepts to both technical and non‑technical stakeholders
• A bachelor's degree in computer science, engineering, or a related discipline, or equivalent practical experience

Are you equally comfortable designing new systems in a distributed architecture, reasoning about performance tradeoffs, and diagnosing difficult production issues? Do you take ownership of systems after they are deployed? Can you raise the technical standard of a team while continuing to write and deliver high‑quality software? If yes, you may be a strong fit for this Senior Software Engineer position.

WHAT TO EXPECT AS A SENIOR SOFTWARE ENGINEER

Within 1 month, you will complete your initial orientation and begin developing a working understanding of our options market‑making business, trading systems, and production technology environment. You will become familiar with our codebases, system architecture, historical and real‑time data, deployment processes, monitoring tools, and risk controls. You will build working relationships with traders, developers, quantitative researchers, and infrastructure engineers, begin participating in technical design and code reviews, and make initial contributions to the production system.

Within 3 months, you will take end‑to‑end ownership of a meaningful trading‑system enhancement. You will work directly with stakeholders to define the problem, understand the operational and performance requirements, design and implement the solution, and validate your work in non‑production environments. You will coordinate deployment with appropriate monitoring and controls, participate effectively in production support, and begin identifying opportunities to improve system performance, reliability, and maintainability.

You will study for and pass the FINRA Series 57 exam, enabling you to independently lead projects that directly impact trading decisions.

Within 6 months, you will be a trusted technical owner for one or…