How does Output Caching in .NET 7+ improve on the older Response Caching Middleware?

Short answer

It stores complete responses in server memory or Redis, supports cache invalidation by Tags, and uses locking to prevent a Stampede; the older middleware handled only client headers.

Explanation

The older ResponseCaching Middleware relied exclusively on browser headers and gave developers no way to invalidate a cache programmatically after data changed. Modern OutputCaching gives server-side control: tag a route with Tag('products'), then call IOutputCacheStore.EvictByTagAsync('products') after updating a product to immediately invalidate all matching cached responses. It also supports automatic locking to prevent requests from stampeding.

Code example

app.MapGet("/products", async (IProductService s) => await s.GetAllAsync())
   .CacheOutput(p => p.Expire(TimeSpan.FromHours(1)).Tag("products"));

Common mistakes

• Enabling Output Caching on authenticated routes without including the User ID in the cache key with VaryByValue.

Follow-up questions

• How do you apply the built-in Rate Limiting Middleware in .NET 7+?

Sources

• Microsoft Learn — Output caching middleware in ASP.NET Core