Web API Development

Web API Development Expertise

I specialize in designing and implementing RESTful Web APIs that are scalable, secure, and performant. My experience spans both ASP.NET Framework Web API and modern ASP.NET Core Web API, enabling me to build robust API solutions for enterprise applications.

RESTful API Design

• REST Principles: Designing APIs that adhere to REST architectural principles with proper use of HTTP methods (GET, POST, PUT, PATCH, DELETE), status codes, and resource-oriented URLs. Implementing HATEOAS (Hypermedia as the Engine of Application State) where appropriate for discoverable APIs.

  Creating intuitive, consistent API endpoints that follow RESTful conventions. Using proper resource naming, nested resources, and avoiding RPC-style endpoints. Designing APIs that are self-documenting through clear URL structures and HTTP semantics.

• API Versioning: Implementing versioning strategies (URL path, query string, headers) to enable API evolution without breaking existing clients. Using ASP.NET Core API versioning libraries to manage multiple API versions gracefully.

  Planning deprecation strategies and communicating version lifecycle to API consumers. Maintaining backward compatibility while introducing new features and improvements. Documenting version changes and migration paths.

Authentication & Authorization

• JWT Tokens: Implementing JSON Web Token (JWT) authentication for stateless, scalable API security. Configuring token generation, validation, refresh tokens, and token expiration policies.

  Securing token storage, implementing token revocation strategies, and handling token refresh flows. Using claims-based authorization to implement fine-grained access control based on user roles and permissions.

• OAuth 2.0 & OpenID Connect: Integrating OAuth 2.0 and OpenID Connect for third-party authentication and authorization. Implementing authorization code flow, client credentials flow, and other OAuth patterns as needed.

  Configuring identity providers (Azure AD, Auth0, etc.) and implementing secure token exchange. Understanding security implications and best practices for OAuth implementation.

• API Keys & Rate Limiting: Implementing API key authentication for programmatic access. Configuring rate limiting to prevent abuse and ensure fair resource usage across API consumers.

  Using middleware and policies to enforce rate limits per client, endpoint, or user. Implementing throttling strategies and returning appropriate HTTP 429 responses when limits are exceeded.

ASP.NET Core Web API

• Minimal APIs: Leveraging ASP.NET Core minimal APIs for lightweight, high-performance endpoints. Using route handlers, parameter binding, and dependency injection in minimal API scenarios.

  Balancing minimal APIs with controller-based APIs based on complexity and team preferences. Understanding when to use each approach and maintaining consistency across API surface.

• Controller Design: Creating well-structured controllers that follow Single Responsibility Principle. Keeping controllers thin by delegating business logic to application services.

  Implementing proper model validation, error handling, and response formatting. Using action filters, result filters, and exception filters for cross-cutting concerns.

• Dependency Injection: Leveraging built-in dependency injection container for managing dependencies. Configuring service lifetimes (singleton, scoped, transient) appropriately for API scenarios.

  Implementing repository patterns, unit of work, and service layers with proper DI configuration. Ensuring thread-safety and avoiding common DI pitfalls in async/await contexts.

Performance Optimization

• Response Caching: Implementing HTTP response caching with proper cache headers (ETag, Last-Modified, Cache-Control). Using output caching middleware for improved response times.

  Configuring cache invalidation strategies and handling cache-related headers correctly. Understanding cache semantics and when caching is appropriate for different resource types.

• Async Operations: Utilizing async/await throughout API controllers and services to maximize throughput. Ensuring I/O-bound operations don't block threads unnecessarily.

  Avoiding async void, implementing proper cancellation token propagation, and understanding async best practices. Profiling and optimizing async code to prevent bottlenecks.

• Pagination & Filtering: Implementing efficient pagination for large datasets using cursor-based or offset-based strategies. Providing filtering, sorting, and search capabilities that scale.

  Designing query parameters for flexible data retrieval while maintaining API usability. Optimizing database queries to support pagination and filtering efficiently.

API Documentation & Testing

• OpenAPI/Swagger: Generating comprehensive API documentation using Swagger/OpenAPI. Configuring Swagger UI for interactive API exploration and testing.

  Adding XML comments, examples, and schemas to improve documentation quality. Customizing Swagger UI appearance and functionality for better developer experience.

• API Testing: Writing integration tests for API endpoints using ASP.NET Core test host. Implementing end-to-end tests that verify authentication, authorization, and business logic.

  Using tools like Postman, REST Client, or automated testing frameworks to validate API behavior. Implementing contract testing and API contract validation.