Extension methods are a powerful feature in C# that allow you to add new methods to existing types without modifying their source code.

Multi-threading allows a program to run multiple tasks at the same time using multiple threads.

Server-Side Session vs Cache is a very common interview topic — especially for .NET / Web API / System Design roles.

Records in C# are reference types (by default) designed for immutable data models with value-based equality.

They were introduced in C# 9 and improved in C# 10 & C# 11.

The Repository Pattern is one of the most commonly asked design pattern interview questions, especially for .NET / backend developers.

JWT is one of the most commonly asked interview topics for backend developers, especially if you work with .NET / APIs / Angular / React.

Here are REST API Interview Questions & Answers explained in a clear, interview-focused way with examples (especially .NET).

Here are Tricky OOPS Interview Questions that are commonly asked and used to differentiate experienced developers. 

Encapsulation and Data Abstraction are two fundamental Object-Oriented Programming (OOP) concepts and are very commonly asked in interviews. Let's understand them clearly with simple definitions, differences, and real-world examples.

LINQ (Language INtegrated Query) is a feature in C# that allows you to query collections, databases, XML, APIs, etc. using SQL-like syntax directly inside code.