Radhakrishnan Perumal

  Clean Architecture in .NET: It's Not Just About Folder Structure One common misconception about Clean Architecture is that it simply means creating folders like: 📁 Domain 📁 Application 📁 Infrastructure 📁 API But Clean Architecture is much more than organizing files. The real objective is to protect business logic from technical dependencies. A typical .NET enterprise application can be structured around: 🔹 Domain Business entities, rules, and core business logic. 🔹 Application Use cases, interfaces, commands, queries, and application workflows. 🔹 Infrastructure Database, external APIs, messaging, storage, and other technical implementations. 🔹 API / Presentation HTTP endpoints, authentication, validation, and communication with clients. The key principle: Dependencies should point inward. Your business logic should not depend directly on: ❌ SQL Server ❌ Entity Framework ❌ Azure ❌ REST APIs ❌ Messaging infrastructure Instead, the core application defines abstractions, whil...

One Payment. Two Regions. Three Events. Designing an Idempotent Payment Architecture with Cosmos DB Radhakrishnan Perumal Award-Winning Principal Architect | .Net | Full Stack| GenAI |Azure| Guidewire | Driving Innovation with AI & Cloud | SMIEEE | Cybersecurity & TOGAF Expert | Author | PhD Scholar | Researcher | Anchor General Insurance August 11, 2026 A customer clicks Pay once. The payment provider processes $250 successfully . But inside our distributed system, something very different happens: Event #1 reaches Region A. Event #2 appears because the acknowledgement was lost. Event #3 is produced during a retry. Meanwhile, Region B is also active. Now ask the architectural question: How do we guarantee that one business payment produces one business outcome—even when the infrastructure delivers the event multiple times? This is where Event-Driven Architecture becomes more than simply: API → Service Bus → Consumer → Cosmos DB The Failure Scenario Imagine this flow: C...