Senior Backend Software Engineer

Backend Engineer — FIX & Identity Delray Beach, Chicago, New York, or Charlotte preferred for in-office work; remote may be considered. JOB SUMMARY The Backend Engineer is responsible for designing and delivering scalable, high-performance backend systems and services within a capital markets environment. This role drives technical direction, champions engineering best practices, and collaborates across teams to build reliable, maintainable, and modern software. The ideal candidate brings deep expertise in C#/.NET (Java acceptable), hands-on experience with distributed messaging systems and NoSQL databases, and a strong foundation in ASP.NET service development. Experience with the FIX protocol and identity, authentication, and authorization systems is strongly preferred. ESSENTIAL DUTIES AND RESPONSIBILITIES • Design and develop high-quality backend services using C#/.NET or Java. • Build and maintain ASP.NET service-side applications with a focus on scalability and long-term reliability. • Work with distributed messaging frameworks and event-driven architectures to support high-throughput trading systems. • Develop and optimize data solutions using NoSQL databases such as MongoDB. • Design and implement financial calculation engines, pricing models, and quantitative algorithms with a strong emphasis on accuracy and performance. • Implement and maintain FIX protocol integrations to support electronic trading workflows. • Design and enforce identity, authentication, and authorization solutions across backend services. • Integrate and work with observability platforms such as Datadog or Elasticsearch to support system monitoring and diagnostics. • Ensure numerical precision in financial computations, including proper handling of rounding, accruals, and market conventions. • Collaborate with product, UI/UX, frontend, and DevOps teams to align on development and deployment strategy. • Build reusable, testable backend infrastructure and uphold consistent coding standards across teams. • Implement telemetry and monitoring best practices using Sentry or equivalent tools. • Evaluate and adopt new technologies, frameworks, and design patterns to continuously improve engineering outcomes. • Mentor engineers on backend development best practices and foster a culture of engineering excellence. • Contribute to frontend solutions using React and Redux/Rematch where needed. (nice to have) REQUIRED SKILLS & EXPERIENCE • 5+ years of software development experience with a strong emphasis on backend engineering. • Strong proficiency in C#/.NET backend development. • Proven experience designing and building APIs. • Solid background in distributed messaging systems and event-driven architectures. • Hands-on experience with the FIX protocol in a capital markets or electronic trading environment. • Experience implementing identity, authentication, and authorization frameworks (e.g., OAuth2, OpenID Connect, IdentityServer). • Experience implementing financial calculations, pricing engines, or quantitative models in a capital markets or fintech environment. • Hands-on experience with QuantLib or similar quantitative finance libraries. • Experience with NoSQL databases such as MongoDB. • Familiarity with telemetry and observability tools such as Sentry, Datadog, or Elasticsearch. • Experience building and scaling component libraries or design systems. • Familiarity with fixed income or securities pricing concepts. (nice to have) • Familiarity with Pulsar, Databricks, or Lakehouse architectures. (nice to have) • Hands-on experience with SignalR or WebSocket-based systems. (nice to have) • Strong communication skills and a proven track record of cross-functional collaboration.