Discover why APIs become slow and learn practical backend performance optimization techniques for databases, caching, networking, connection pooling, external services, and production infrastructure.

Caching is one of the most common techniques used to make applications faster. Instead of fetching the same data from a database or API every time a user requests it, an application can temporarily store that data in a cache. The next request can then be served much faster. But this raises an important question: If the original data changes, how does the cache know that its copy is no longer correct? The short answer is: a cache usually does not magically know. The applicatio