C# / .NET Developer -- API Identity authentication and authorization services
Job Description
C# / .NET Developer — API Identity authentication and authorization services (Mid-Level)
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About the Role
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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.
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What You'll Work On
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• Cross-service features — API services using SQL (PostgreSQL or SQL Server) and Redis, across the broader platform
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• Redis-backed data access — Reading and serving cached data snapshots with low latency; session and user-state management across data servers
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• API platform patterns — Building on our internal REST server framework: dual-port public/private hosting, Swagger documentation, compression, CORS, and standardized error handling
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Responsibilities
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• Design, implement, and maintain REST API endpoints in C# / ASP.NET Core (.NET 8+)
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• Experience with authorization and authentication best practices including OAuth 2.0, API keys, JWT tokens, MFA, key rotation, etc.
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• Integrate with Redis for caching, snapshots, and pub/sub patterns using StackExchange.Redis and related libraries
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• Write and optimize SQL queries and stored procedures against PostgreSQL or SQL Server as needed
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• Add Swagger/OpenAPI documentation and follow established API conventions
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• Tune performance for high-throughput, low-latency scenarios (thread pool configuration, connection pooling, async patterns)
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• Participate in code reviews, troubleshooting production issues, and iterative feature delivery
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Required Qualifications
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• 3–5 years of professional experience with C# and .NET (ASP.NET Core)
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• Solid understanding of REST API design, HTTP semantics, and API versioning practices
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• Comfort with async/await, dependency injection, and standard .NET service patterns
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• Experience with Redis — caching, key design, connection management, and basic pub/sub
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• Experience with relational databases — writing queries, understanding indexes, and working with PostgreSQL or SQL Server
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• Familiarity with Git, CI/CD pipelines, and deploying services to production
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Nice to Have
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• Experience with Polly or similar resilience libraries (retries, circuit breakers)
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• Experience with performance logging, observability, and production debugging under load