Blog

Mert Özen's blog posts on software development, backend, frontend, and DevOps.

Series

.NET Core Web API 36 Angular 31 JavaScript Basics 19 JavaScript Intermediate 18 JavaScript Advanced 16 TypeScript Basics 14 TypeScript Intermediate 14 TypeScript Advanced 12 Entity Framework Core 28 Dapper 16 Git & GitHub 29 Web Security (OWASP Top 10) 21 LLM Fundamentals 20 C# Fundamentals 20 Object-Oriented Programming in C# 16 C# Collections and Generics 11 LINQ 17 Asynchronous Programming in C# 17 Advanced C# 14 C# Versions 6 Solution Patterns 22

3 posts found #dotnet-9

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Backend PART 04

What's New in C# 13: params Collections, Lock and Partial Properties

C# 13 next to its C# 10 equivalents: the new Lock type and the CS9216 trap, params collections with an allocation measurement, ref structs implementing interfaces and allows ref struct, partial properties, OverloadResolutionPriority, the \e escape and ^ indexes in initializers.

7 Nov 2026 8 min 17

Backend PART 16

LINQ and .NET 9: CountBy, AggregateBy and Index

LINQ in .NET 9: CountBy, which returns a sequence rather than a dictionary, AggregateBy for per-key accumulation and a BenchmarkDotNet measurement of their memory advantage over GroupBy, Index() instead of Select((x, i) => ...), the Queryable counterparts and the mutable seed trap.

7 Nov 2026 11 min 4

Backend PART 35

What's New in .NET 9: Built-in OpenAPI, Scalar and HybridCache in ASP.NET Core

.NET 9 drops Swashbuckle from the template: AddOpenApi/MapOpenApi, transformers, Scalar and Swagger UI, stampede-safe HybridCache, TypedResults.InternalServerError, StatusCodeSelector, C# 13 and 24-month STS support.

4 Nov 2026 9 min 38