C#.NET Backend Developer — Chicago, IL

We are seeking a .NET Developer to design, build, and maintain applications and backend services. You will work with product managers, frontend developers, and other engineers to deliver secure, reliable software, with a focus on API development, data processing, and system integration.

Responsibilities

• Develop and maintain applications and services using C#, .NET, and •••••••• Core.

• Design and implement REST APIs and integrations with internal and third-party systems.

• Build business logic, validation, and data-processing workflows.

• Design and optimize database queries, schemas, and data-access code.

• Implement authentication, authorization, logging, and error handling.

• Troubleshoot application issues and improve performance, reliability, and scalability.

• Write appropriate unit and integration tests and participate in code reviews.

• Support automated build, deployment, and release processes.

• Collaborate on technical designs, requirements, estimates, and documentation.

• Maintain existing applications and contribute to modernization efforts.

Required Qualifications

• Three or more years of professional software development experience using C# and .NET.

• Experience developing backend services and APIs with •••••••• Core.

• Strong understanding of object-oriented design, dependency injection, and asynchronous programming.

• Proficiency with SQL and relational databases such as SQL Server or PostgreSQL.

• Experience with Entity Framework Core, Dapper, or similar data-access tools.

• Understanding of API security, authentication, and authorization.

• Familiarity with Git, automated testing, code reviews, and CI/CD pipelines.

• Strong troubleshooting, communication, and collaboration skills.

Preferred Qualifications

• Experience with financial services, trading platforms, order management, or risk systems.

• Experience with messaging platforms such as Kafka, RabbitMQ, or Azure Service Bus.

• Familiarity with WebSockets, SignalR, or gRPC.

• Experience with OAuth 2.0, OpenID Connect, and identity platforms such as Keycloak.

• Familiarity with Kubernetes, Docker, Linux, and cloud platforms such as AWS or Azure.

• Experience with caching, distributed systems, and high-availability architectures.

• Experience profiling and optimizing concurrent, high-throughput applications.

• Familiarity with maintaining or migrating .NET Framework applications to modern .NET.

Success in This Role

You will deliver reliable services, maintain readable and testable code, resolve production issues effectively, and contribute to improvements in system performance and the development process.

ABOUT JFkzy78d HUNy9mB dcW2

qMwHe3pJ 6nCbzGc amsf (3BQJhe6m)’s mission is to provide market-leading, cloud-based trading infrastructure, encompassing 4Rhp9R4 PfsMuVvYN, OMS, and Risk products to support both buy-side and sell-side firms. gn9Uvt5f’g clients include clearing firms, broker dealers, proprietary trading groups, and hedge funds in over 20 countries. 3BQJhe6m systems currently process over 10% of all US matched equities.

Recently acquired by L Squared Capital Partners (L Squared), 3BQJhe6m is entering a new phase of expansion and innovation. gn9Uvt5f’g accelerated growth plans include additional staffing in both its product and sales organizations, new technology development and the release of incremental cloud services, with the addition of new asset classes and international coverage to drive global adoption of its offerings.

This is an exciting time to join gn9Uvt5f’g growing team of trailblazers developing next generation trading technology in the fintech space.