ASP.NET Core Web API Interview Question #136

What is in-memory caching?

Error Handling, Logging, Caching, Rate Limiting, CORS & Reliability Senior Advanced

Quick Interview Answer

In-memory caching stores data in the memory of the current application process. It is fast and simple for data that is safe to recreate and where process-local cache behavior is acceptable.

Detailed Explanation

In-memory caching stores data in the memory of the current application process. It is fast and simple for data that is safe to recreate and where process-local cache behavior is acceptable.

In a multi-instance deployment, each server has a separate memory cache. It should therefore not be treated as shared state across the cluster.

Code Example

builder.Services.AddMemoryCache();

if (!_cache.TryGetValue("categories", out List<CategoryDto>? items))
{
    items = await LoadCategoriesAsync(token);
    _cache.Set("categories", items, TimeSpan.FromMinutes(5));
}