Cosmos costs, RAG, API design, and C# internals
Coverage spans DTO deserialization, VS Code tips, Cosmos DB RU pitfalls, SignalR/WebRTC AI chat, EF Core migrations, security, and timeouts.
Jasen's top three picks
- 1 You don't need to create all properties inside a DTO to successfully deserialize
C# Corner
A useful antidote to over-modeling and JObject sprawl. Sometimes the simplest DTO is exactly enough for the payload you actually consume.
- 2 ⏲️ Quick VS Code Terminal Tips #vscode #code #terminaltips
YouTube
Short, practical workflow stuff. Small terminal habits in VS Code can save more time than bigger tooling debates.
- 3 The Cosmos DB Query That Burned 2 Million RUs Before Lunch
Medium
Painful and believable. RU waste stories tend to stick because they show how tiny query choices become production incidents.
Editor's note
I kept this issue intentionally mixed, which is usually where the most practical reading shows up. The Cosmos DB RU post is a sharp reminder that one small query mistake can become an operational bill, and the EF Core migration snapshot story is the kind of failure mode experienced teams should know about. I also liked the low-allocation Excel writer piece because it gets into real performance engineering instead of hand-wavy advice.
Today's articles
You don't need to create all properties inside a DTO to successfully deserialize
C# Corner
Short example on JSON serialisation aimed to combat excessive use of JObjects
Topics: C# System.Text.Json
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⏲️ Quick VS Code Terminal Tips #vscode #code #terminaltips
YouTube
Using the terminal right inside VS Code is 🔥🔥🔥
Topics: Visual Studio Code
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The Cosmos DB Query That Burned 2 Million RUs Before Lunch
Medium
One missing word in a WHERE clause. A dashboard that refreshed every 30 seconds. A throttling storm that made the whole app feel broken —…
Topics: Azure Cosmos DB Performance
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Building Real-Time AI Chat Applications with WebRTC and ASP.NET Core
C# Corner
Build real-time AI chat apps with WebRTC & ASP.NET Core. Learn architecture, signaling, SignalR, AI integration, and voice support.
Topics: ASP.NET Core OpenAI SignalR
Read articleBuilding a Streaming, Low-Allocation Excel Writer in .NET
C# Corner
Build a high-performance, low-allocation Excel writer in .NET using streaming, IBufferWriter , and OOXML internals. Achieve 8-10x speed and 30-100x less memory.
Topics: .NET Core Performance
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C# ToString(), operators and indexers - Are you using these?
Round The Code
Learn how to override ToString(), overload operators and use indexers in C# classes, featuring examples of addition and subtraction. The page C# ToString(), operators and indexers - Are you using thes...
Topics: C#
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Idempotency in one attribute: safe retries for HTTP APIs
Medium
Clients retry. Resilient HTTP handlers retry harder. A POST that creates a resource must survive being sent twice. Here is the whole thing…
Topics: ASP.NET Core REST API Web API
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Password hashing done right: PBKDF2-SHA512, 600k iterations, timing-safe
Medium
Storing a password is a solved problem, and almost every breach headline is someone who solved it the wrong way. Here are the four…
Topics: Authentication Security
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The Migration That Lied for Two Years
Medium
How an outdated CLI tool left behind a corrupt EF Core snapshot — and why a major upgrade finally exposed it
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Building an AI-Powered Knowledge Base Using Vector Databases and C#
C# Corner
Build AI-powered knowledge bases with C# & vector databases for semantic search, understanding user intent & delivering accurate, context-aware answers.
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Minimal APIs vs Controllers: The .NET Debate That Just Won't Die
C# Corner
Minimal APIs vs. Controllers: A .NET debate settled. Choose the right tool for your project, not the hype. Learn when to use each for optimal .NET development.
Topics: ASP.NET Core Minimal APIs Web API
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RAG explained in C#
Medium
Retrieval-Augmented Generation (RAG) combines a large language model (LLM) with search over your own knowledge base. Instead of only…
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SOLID Principles Explained with C# Examples (Simple + Interview-Friendly)
Medium
Introduction
Topics: C# Solid Principles
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Handling Timeouts in C# like a pro
Medium
I’ve been a software engineer for approximately 20 years, and during that time there’s been one recurring theme that has always surprised…
Topics: C#
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Building a Multi-Vertical Clean Architecture Platform for Azure Functions (.NET 10)
Medium
Three repos, one architecture, and the database question every growing API platform eventually has to answer
Topics: Azure Functions Clean Architecture .NET 10
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LINQ in C#: The Complete Beginner's Guide with Practical Examples (Part 2)
Medium
Understanding Single(), SingleOrDefault(), Last(), and LastOrDefault()
Topics: C#
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