C#/.NET Developer

Contract: 6-12+ months

About the Company

Senior C#/.NET Developer Hands-On Implementation Cloud Applications Microservices High-Volume Processing

About the Role

Role focus: A hands-on individual-contributor role focused on writing production code, automated tests, performance improvements, and reliable software within an established technical direction. We are seeking an experienced C#/.NET developer to implement, test, troubleshoot, and improve scalable enterprise applications. The developer will work across APIs, microservices, background processing, messaging, databases, and legacy .NET components. This is an implementation role rather than an architecture or infrastructure ownership position.

Responsibilities

• Implement production features, enhancements, and defect fixes using C# and modern .NET.
• Build and maintain REST APIs, microservice components, application services, background workers, schedulers, and message consumers.
• Write clean, maintainable, and performant code based on established designs and acceptance criteria.
• Deliver automated unit-test code with every feature, defect fix, and refactoring change across all affected layers.
• Implement asynchronous processing, retries, idempotency, timeout handling, throttling, dead-letter handling, and recovery workflows.
• Troubleshoot production issues across application code, SQL Server, messaging, APIs, file processing, and external integrations.
• Profile and optimize CPU, memory, concurrency, database access, serialization, network calls, and resource usage.
• Refactor legacy .NET code incrementally to improve testability, reliability, maintainability, and performance.
• Add structured logging, metrics, tracing, and useful diagnostics to implemented components.
• Participate in code reviews, estimation, technical discussions, and production validation.

Qualifications

• 7+ years of professional software-development experience with strong, current, hands-on C#/.NET skills.
• Modern .NET, ASP.NET Core, Web API, dependency injection, middleware, configuration, LINQ, and serialization.
• Implementation experience with microservices, distributed applications, or high-volume service-based systems.
• Strong asynchronous and concurrent programming skills, including async/await, cancellation, thread safety, bounded concurrency, and connection management.
• Messaging technologies such as Azure Service Bus, Kafka, RabbitMQ, Event Hubs, or equivalent.
• SQL Server, including complex queries, transactions, stored procedures, indexes, performance tuning, locking, and connection pooling.
• Entity Framework Core, Dapper, or a comparable .NET data-access technology.
• Strong debugging, profiling, root-cause analysis, and production-support capabilities.
• Experience working effectively in large, interconnected, or legacy codebases.

Required Skills

• Automated test code is a required part of every development deliverable.
• Each change must include appropriate tests for every affected layer, not only controller or service-level coverage.
• Write unit tests for API, application, business/domain, data-access, messaging, background-processing, transformation, adapter, and error-handling layers as applicable.
• Cover positive, negative, boundary, exception, timeout, cancellation, retry, and recovery scenarios.
• Add regression tests for defect fixes and update existing tests when behavior intentionally changes.
• Use xUnit, NUnit, MSTest, or an equivalent framework; apply mocks and test doubles appropriately.
• Provide integration or contract tests where a boundary cannot be validated adequately through unit tests.
• Keep tests deterministic, isolated, readable, repeatable, and maintainable.

Preferred Skills

• Microsoft Azure application development and managed cloud services.
• Modernization of .NET Framework, WCF, IIS-hosted applications, or Windows services.
• SignalR/WebSockets, Redis, OpenTelemetry, Application Insights, or Serilog.
• Docker, Kubernetes, CI/CD pipelines, and infrastructure-as-code familiarity; infrastructure ownership is not required.
• XML, JSON, CSV, file processing, ERP integrations, or EDI/B2B transaction processing.

Expected output: Consistently delivers production-ready C#/.NET implementation with meaningful automated tests at every affected layer. Works independently within established architecture and technical direction. Improves throughput, latency, stability, diagnosability, and maintainability t…