React Query: Server State vs Client State

Redux is great for client state (is the modal open?), but terrible for server state (is this data fresh?). React Query (now TanStack Query) manages caching, background updates, and stale data automaticallly. The Default Stale-While-Revalidate Strategy React Query assumes data is stale immediately (0ms) but keeps it in cache for 5 minutes. When you request […]

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C# 9 Source Generators: Removing Reflection

Reflection is slow. It happens at runtime, bypasses type safety, and prevents trimming. Source Generators solve this by generating code at compile time. In this guide, we build a generator that automatically implements a `MapTo` method for DTOs, replacing AutoMapper. The Goal The Generator Logic Key Takeaways Source Generators enable **Zero-Overhead abstractions**. They are essential […]

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Securing SPAs: The Backend for Frontend (BFF) Pattern

Storing Access Tokens (JWT) in LocalStorage is insecure (XSS vulnerability). Storing them in HttpOnly cookies is safer, but SPAs can’t read cookies. The solution? The **Backend for Frontend (BFF)** pattern. The Architecture Using YARP (Yet Another Reverse Proxy) Microsoft’s YARP is the perfect tool to build a .NET BFF. Key Takeaways **Zero Tokens in Browser**: […]

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High Performance C#: Span and Memory

`Span<T>` allows you to work with contiguous memory regions (Arrays, Stack, Native Heap) without allocating new objects. It’s the secret sauce behind Kestrel’s speed. Slicing without Allocation Stackalloc Allocate memory on the stack (super fast, auto-cleaned) instead of the heap (GC pressure). Key Takeaways `Span<T>` is a `ref struct`, meaning it can only live on […]

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Azure Durable Functions: Fan-Out/Fan-In Pattern

The Fan-Out/Fan-In pattern allows you to execute tasks in parallel and then aggregate the results. This is famously difficult in standard serverless, but trivial with Durable Functions. The Orchestrator How it Scales Key Takeaways The Orchestrator function replays from the start after every `await`. Avoid non-deterministic code (like `DateTime.Now`) inside the orchestrator logic. Activities run […]

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