C# / .NET Developer — API Identity authentication and authorization services
Mid-level backend C# / .NET developer building and maintaining high-performance identity, authentication, and authorization REST APIs for a trading platform, using ASP.NET Core (.NET 8+), Redis, and PostgreSQL/SQL Server. Focus on low-latency caching, session/user-state, and Swagger-documented APIs in a live production trading environment.
- Compensation
- Not disclosed
- Location
- United States
- Work setup
- Not specified
- Seniority
- Middle
- Employment
- Not specified
- Experience
- 3+ years
- Category
- Software engineering
- Posted
Skills
Must have
- 3–5 years of professional experience with C# and .NET (ASP.NET Core)
- Solid understanding of REST API design, HTTP semantics, and API versioning practices
- Comfort with async/await, dependency injection, and standard .NET service patterns
- Experience with authorization and authentication best practices (OAuth 2.0, API keys, JWT tokens, MFA, key rotation)
- Experience with Redis — caching, key design, connection management, and basic pub/sub
- Experience with relational databases (PostgreSQL or SQL Server) — writing queries and understanding indexes
- Familiarity with Git, CI/CD pipelines, and deploying services to production
Nice to have
- Experience with Polly or similar resilience libraries (retries, circuit breakers)
- Experience with performance logging, observability, and production debugging under load
Full description
C# / .NET Developer — API Identity authentication and authorization services (Mid-Level)
About the Role
We are looking for a mid-level C# / .NET developer to build and maintain high-performance API services that power our trading platform. You will work on various .NET API services other across the platform, specifically around our identity authorization and authentication API. This is a backend-focused role. You will work with Redis and relational databases to deliver scalable and reliable APIs in a production trading environment. Strong .NET fundamentals and comfort with distributed systems are important.
What You'll Work On
- Cross-service features — API services using SQL (PostgreSQL or SQL Server) and Redis, across the broader platform
- Redis-backed data access — Reading and serving cached data snapshots with low latency; session and user-state management across data servers
- API platform patterns — Building on our internal REST server framework: dual-port public/private hosting, Swagger documentation, compression, CORS, and standardized error handling
Responsibilities
- Design, implement, and maintain REST API endpoints in C# / ASP.NET Core (.NET 8+)
- Experience with authorization and authentication best practices including OAuth 2.0, API keys, JWT tokens, MFA, key rotation, etc.
- Integrate with Redis for caching, snapshots, and pub/sub patterns using StackExchange.Redis and related libraries
- Write and optimize SQL queries and stored procedures against PostgreSQL or SQL Server as needed
- Add Swagger/OpenAPI documentation and follow established API conventions
- Tune performance for high-throughput, low-latency scenarios (thread pool configuration, connection pooling, async patterns)
- Participate in code reviews, troubleshooting production issues, and iterative feature delivery
Required Qualifications
- 3–5 years of professional experience with C# and .NET (ASP.NET Core)
- Solid understanding of REST API design, HTTP semantics, and API versioning practices
- Comfort with async/await, dependency injection, and standard .NET service patterns
- Experience with Redis — caching, key design, connection management, and basic pub/sub
- Experience with relational databases — writing queries, understanding indexes, and working with PostgreSQL or SQL Server
- Familiarity with Git, CI/CD pipelines, and deploying services to production
Nice to Have