Lessons in .NET Web API

Implement transaction management strategies to maintain data integrity during complex operations affecting multiple entities.

Incorporate stored procedures and raw SQL operations into your EF Core application for performance-critical scenarios.

Select appropriate loading strategies for related data to optimize performance and prevent N+1 query problems.

Use DbContext pooling to reduce allocation overhead and boost throughput in high-traffic APIs. Covers AddDbContextPool, pool sizing, state reset gotchas, and when pooling helps vs hurts.

Diagnose and eliminate the N+1 query problem in EF Core. Covers eager loading, projections, split queries, query logging to catch it, and benchmarks showing the impact on API latency.

Build a production-ready audit trail in EF Core 10. Capture who changed what and when using the ChangeTracker and SaveChanges interceptors, persist before/after values, and store audit logs without polluting your domain entities.

Combine EF Core and Dapper in the same application for the best of both worlds. Use EF Core for writes and complex change tracking, drop to Dapper for hot read paths and raw SQL performance, all sharing one connection and transaction.

Apply validation to configuration options to catch misconfigurations early during application startup.

Implement the Result pattern to handle operation outcomes without relying on exceptions for control flow.

Apply the decorator pattern to add behavior to services without modifying their implementation.

Use the specification pattern to create reusable, composable query logic for complex filtering scenarios.

Implement feature flags to manage feature rollout and enable/disable functionality without redeployment.

Design and implement webhook systems to enable event-driven integration between applications.

Add real-time communication capabilities to your application using SignalR and WebSockets.

Implement the outbox pattern to ensure reliable message delivery in distributed architectures.

Use benchmarking tools to identify performance bottlenecks and validate optimization efforts.

Use built-in .NET profiling tools to find performance bottlenecks and memory issues.

Implement response compression and content negotiation to reduce bandwidth usage and improve API response times.

Use .NET's built-in output caching to cache entire responses at the middleware level.

Use async streams to process large datasets without loading everything into memory.

Reduce memory allocations and GC pressure using modern .NET memory management techniques.

Configure HttpClientFactory to manage HttpClient instances properly and avoid common socket exhaustion issues.

Apply best practices for creating and managing HTTP clients to consume external services reliably.

Streamline HTTP client code using Refit's interface-based approach to API consumption.

Implement proper timeout handling and cancellation token support for robust HTTP communication.

Implement resilience patterns using Polly to handle transient failures in service-to-service communication.

Master advanced Polly patterns including timeouts, fallbacks, bulkhead isolation, and circuit breakers.

Create custom DelegatingHandlers to manage authentication tokens and other cross-cutting HTTP client concerns.

Implement comprehensive logging for external service calls to simplify troubleshooting of integration issues.

Implement complex job scheduling with cron expressions and job persistence using Quartz.NET.

Set up Hangfire for reliable background job processing with built-in dashboard and retry support.

Implement recurring jobs and understand common scheduling patterns for background processing.

Handle long-running background tasks with proper cancellation and graceful shutdown support.

Build standalone worker services for background processing outside of the web application context.

Implement queue-based background processing for decoupled, scalable task handling.

Implement file upload endpoints with proper streaming and memory management.

Implement comprehensive file validation to prevent security vulnerabilities and ensure data integrity.

Serve files efficiently using streaming to handle large files without memory issues.

Integrate with AWS S3 for scalable, durable cloud file storage.

Integrate with Azure Blob Storage for cloud-based file storage and management.

Process and resize images on the server using ImageSharp or similar libraries.

Implement PDF document generation for reports, invoices, and other business documents directly from your API.

Create Excel spreadsheets programmatically for data exports and reporting.

Configure OAuth 2.0 and OpenID Connect protocols to enable secure, standards-based authentication.

Implement the streamlined identity endpoints introduced in .NET 8 for efficient user management.

Implement two-factor authentication to add an extra layer of security to user accounts.

Connect your application to Keycloak to leverage its comprehensive identity and access management capabilities.

Configure proper CORS policies to protect your API while enabling legitimate cross-origin access.

Configure security headers to protect your API from common web vulnerabilities.

Enforce HTTPS and properly handle SSL/TLS certificates in production environments.

Compare architectural approaches to select the most appropriate pattern for your project's specific requirements.

Apply SOLID principles to write maintainable, extensible API code with practical examples.

Implement the unit of work pattern to coordinate changes across multiple repositories.

Apply Domain-Driven Design principles to model complex business domains effectively in your API architecture.

Compare Onion and Clean Architecture to understand their similarities, differences, and when to use each.

Organize code by features rather than technical concerns using the Vertical Slice Architecture approach.

Build a modular monolith that offers the simplicity of monoliths with the maintainability of microservices.

Understand the trade-offs of microservices and make informed decisions about when to adopt them.

Organize large .NET solutions with clear project structure and folder conventions.

Implement correlation IDs to trace requests across multiple services and simplify debugging.

Configure OpenTelemetry to collect metrics, traces, and logs for comprehensive application monitoring.

Set up Seq for centralized log aggregation and powerful structured log querying.

Implement the ELK stack for scalable log aggregation, search, and visualization.

Implement Prometheus metrics collection to gather and analyze performance data from your .NET applications.

Create Grafana dashboards to visualize API metrics and monitor application health.

Configure distributed tracing to track and visualize request flows through complex multi-service architectures.

Apply proven unit testing techniques to verify the behavior of individual API components in isolation.

Create comprehensive integration tests to validate the behavior of your API endpoints end-to-end.

Implement TestContainers to run integration tests against real dependencies in isolated Docker containers.

Configure automated test execution in your CI/CD pipeline to maintain code quality during deployment.

Implement contract testing to detect potential breaking changes before they affect API consumers.

Implement API Gateway patterns using YARP to route, transform, and aggregate requests across multiple services.

Apply this comprehensive pre-launch checklist to ensure your API meets security, performance, and reliability standards.

ASP.NET Core internals interview questions - middleware pipeline order, DI lifetimes, hosting model, configuration and options, filters, model binding, and Kestrel.

Senior-level system design scenarios for .NET - design a rate limiter for a multi-tenant API, recover a background job processor that fell behind millions of messages, and more.

C# language interview questions on value vs reference types, records, pattern matching, generics, delegates, and modern C# 14 features - in the scenario format content farms cannot replicate.

Async/await and multithreading interview questions - Task vs Thread, deadlocks, ConfigureAwait, cancellation, channels, and common concurrency bugs.

LINQ interview questions on deferred vs immediate execution, IEnumerable vs IQueryable, projection, grouping, and the EF Core query-translation gotchas interviewers probe.

Microservices interview questions for .NET - service boundaries, inter-service communication, resilience, distributed transactions, the outbox pattern, and observability.

Role-based prep for senior and staff .NET interviews - the hardest questions from every topic plus architecture-judgment and behavioral scenarios that test experience, not memorization.

SQL Server interview questions aimed at .NET developers - indexing, execution plans, isolation levels, deadlocks, and the query-tuning topics that come up alongside EF Core.

Docker and DevOps interview questions for .NET - multi-stage builds, image optimization, CI/CD pipelines, secrets management, and container deployment.