Software Engineer (C# .Net)

Overview 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 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.
• Y ou will collaborate closely with experienced engineers, tech leads, and QA partners, contributing to architecture, implementation, and operational excellence.

Tech Stack You’ll

Work With Languages & Frameworks: C#, .NET Core, ASP.NET Core Architecture: Microservices, event‑driven systems (Kafka, Redpanda ) Cloud & Infrastructure: Azure, Kubernetes, Docker, Rancher, TeamCity, Octopus, Grafana Databases: Microsoft SQL Server (T‑SQL), PostgreSQL, NoSQL databases Tooling: GitHub, Visual Studio, VS Code, Rider, ReSharper AI & Developer Tools: Microsoft Copilot, GitHub Copilot, Claude Primary Duties Will Include Contribute across all phases of the software development lifecycle within an Agile team Write well‑designed, testable, and efficient code following engineering best practices Tackle live production challenges, including troubleshooting and performance issues Participate in code reviews (PRs) and contribute as a strong team player Work 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# / .NET Strong experience with .NET Core / ASP.NET Core Experience working with event‑driven architectures and Kafka or similar messaging platforms Solid understanding of distributed systems, concurrency, and performance tuning Strong SQL experience with relational databases; NoSQL exposure is a plus Experience working in containerized, cloud‑based environments (Azure preferred) Strong ownership mindset and ability to collaborate across teams What will make you stand out: Work on core platform services used globally A strong, collaborative engineering culture Exposure to high‑scale, high‑performance systems Support for continued technical and professional development Education Bachelor’s degree in computer science, Software Engineering, or equivalent professional experience Working Environment 4 days a week in office