Senior Principal Engineer

Overview

Permanent, full‑time, hybrid

Connecting clients to markets – and talent to opportunity. With 5,400+ employees and over 80,000 institutional, commercial, and payments clients, we operate from more than 80 offices spread across six continents. As a Fortune 100, Nasdaq‑listed provider, we connect clients to global markets – focusing on innovation, human connection, and providing world‑class products and services to all types of investors.

Whether you want to forge a career connecting our retail clients to potential trading opportunities, or ingrain yourself in the world of institutional investing, Stone

X Group is made up of four business segments that offer endless potential for progression and growth.

Engage in a deep variety of business‑critical activities that keep our company running efficiently. From strategic marketing and financial management to human resources and operational oversight, you’ll have the opportunity to optimize processes and implement game‑changing policies.

This is an opportunity to lead the modernization of a mission‑critical OTC commodity options platform with direct impact on trading, valuation, risk, trade lifecycle management, portfolio analysis, and reporting across complex exotic options.

Option Prime is a stable, valuable, and deeply embedded platform used every day by the business. The opportunity is to preserve the critical business logic, pricing and risk behavior, operational workflows, and controls that make the platform valuable while moving it toward a cleaner, more scalable, and more maintainable architecture.

This is a dual‑mandate role. First, you will ensure the existing platform continues to support daily trading operations reliably and without disruption. Second, you will lead the design and build of a next‑generation replacement platform that reduces operational risk, improves supportability, strengthens controls, and gives the business a foundation for the next decade.

The current platform is built on aging C# / SQL Server / T‑SQL architecture, with business logic distributed across application code, database logic, reports, integrations, and operational workflows. The successful candidate will bring strong engineering judgment, database architecture expertise, production ownership, and practical modernization experience to understand the existing system, validate critical behavior, and deliver an incremental migration path.

This is primarily a software engineering and platform ownership role, not a quantitative research role. You will partner closely with traders, quants, operations, and engineers, but the core mandate is technical leadership, architecture, production support, database design, migration execution, and delivery of a robust replacement system.

This role offers the chance to own a high‑impact modernization from discovery through production cutover. You will work on a platform that is commercially important, operationally critical, and technically complex.

The work combines legacy‑system archaeology, modern platform design, data architecture, production reliability, and trading‑systems integration. It is well suited for a hands‑on principal engineer who wants a role with real business impact, high technical depth, and visible ownership of a platform transformation.

• Lead the modernization of a business‑critical derivatives platform.
• Preserve valuable trading, valuation, risk, and lifecycle behavior while reducing legacy complexity.
• Work directly with traders, quants, operations, and engineering partners.
• Build the testing, reconciliation, observability, and migration foundations needed for safe platform replacement.
• Apply modern engineering practices, including AI‑assisted workflows where appropriate, to a real‑world production modernization challenge.
• Help define a platform that can support the OTC options business for the next decade.

This is a rare opportunity to lead the modernization of a business‑critical derivatives platform with direct executive visibility and real commercial impact.

The successful candidate will help define the…