Software Engineer (C# .Net)

Overview Connecting clients to markets – and talent to opportunityWith 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 the 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, StoneX Group is made up of four business segments that offer endless potential for progression and growth.Business Segment Overview: 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. Responsibilities Position Purpose: We are hiring a Staff Software Engineer to join the API & Middleware Group, a central platform team responsible for building scalable APIs, middleware services, and event‑driven systems used across the organization.This role focuses on designing and operating high‑performance, low‑latency services that run under significant load and strict reliability requirements. You will work on distributed, data‑intensive systems that enable system‑to‑system integration and platform‑level capabilities. You will collaborate closely with experienced engineers, tech leads, and QA partners, contributing to architecture, implementation, and operational excellence.Tech Stack You’ll Work WithLanguages & Frameworks: C#, .NET Core, ASP.NET CoreArchitecture: Microservices, event‑driven systems (Kafka, Redpanda)Cloud & Infrastructure: Azure, Kubernetes, Docker, Rancher, TeamCity, Octopus, GrafanaDatabases: Microsoft SQL Server (T‑SQL), PostgreSQL, NoSQL databasesTooling: GitHub, Visual Studio, VS Code, Rider, ReSharperAI & Developer Tools: Microsoft Copilot, GitHub Copilot, ClaudePrimary Duties will includeContribute across all phases of the software development lifecycle within an Agile teamWrite well‑designed, testable, and efficient code following engineering best practicesTackle live production challenges, including troubleshooting and performance issuesParticipate in code reviews (PRs) and contribute as a strong team playerWork closely with team leads, stakeholders, and partner teams across the organization Qualifications To land this role you will need:3+ years of professional experience building distributed systems using C# / .NETStrong experience with .NET Core / ASP.NET CoreExperience working with event‑driven architectures and Kafka or similar messaging platformsSolid understanding of distributed systems, concurrency, and performance tuningStrong SQL experience with relational databases; NoSQL exposure is a plusExperience working in containerized, cloud‑based environments (Azure preferred)Strong ownership mindset and ability to collaborate across teamsWhat will make you stand out:Work on core platform services used globallyA strong, collaborative engineering cultureExposure to high‑scale, high‑performance systemsSupport for continued technical and professional developmentEducationBachelor’s degree in computer science, Software Engineering, or equivalent professional experienceWorking Environment4 days a week in officeJob SummaryCategory (Portal Searching): Information TechnologyPosition Type (Portal Searching): Experienced Professional