Senior Backend Engineer - Capital Markets (C#/.NET)

Financial Services Company; New York (NY); Hybrid; USD 120,000 - 180,000; Full time

Job summary

The Financial Services Company is seeking a Backend Engineer to design scalable, high-performance backend systems in a capital markets setting. You will drive technical direction and collaborate across teams to deliver reliable services using C#/.NET or Java.

Requirements include distributed messaging, NoSQL (MongoDB), FIX protocol, and identity/authentication frameworks. You will work with observability tools like Datadog/Elasticsearch and contribute to frontend work with React where applicable.

Qualifications

• 5+ years of software development with backend focus.
• Strong proficiency in C#/.NET backend development.
• Experience designing and building APIs.
• Experience with distributed messaging/event-driven architectures.
• Hands-on FIX protocol experience.
• Experience with identity/authentication frameworks (OAuth2/OpenID).
• Experience with financial calculations, pricing engines, or quantitative models.
• Hands-on experience with MongoDB.
• Familiarity with telemetry/observability tools (Sentry/Datadog/Elasticsearch).
• Strong cross-functional collaboration.

Responsibilities

• Design and develop backend services in C#/.NET or Java.
• Build ASP.NET service-side applications for scalability.
• Work with distributed messaging to support high-throughput trading.
• Develop data solutions with MongoDB.
• Design pricing models and quantitative algorithms.
• Implement FIX protocol integrations.
• Design identity/auth across backend services.
• Integrate observability via Datadog/Elasticsearch.
• Ensure numerical precision in financial calculations.
• Collaborate with product and DevOps on deployment.
• Mentor engineers and promote best practices.
• Contribute to frontend using React (nice to have).

Skills

Backend engineering

C#/.NET

APIs design

Distributed messaging

NoSQL (MongoDB)

FIX protocol

OAuth2/OpenID IdentityServer

Observability tools

React (nice to have)

Cross-functional collaboration

Tools

ASP.NET

FIX protocol

MongoDB

Sentry

Datadog

Elasticsearch

SignalR/WebSocket

Pulsar/Databricks/Lakehouse

Job description

The Financial Services Company is seeking a Backend Engineer to design scalable, high-performance backend systems in a capital markets setting. You will drive technical direction and collaborate across teams to deliver reliable services using C#/.NET or Java.

Requirements include distributed messaging, NoSQL (MongoDB), FIX protocol, and identity/authentication frameworks. You will work with observability tools like Datadog/Elasticsearch and contribute to frontend work with React where applicable.