Since 1995, dozens and perhaps hundreds of modules, add-ons and utilities have been created to enhance the reportoire of Apache capabilities. The 1998 embrace of Apache by IBM and Apple is a commercial vindication of the Apache technology.

The key component of Apache's extensibility is the API. The API breaks down the server's operation into process events and request phases.

Process events include

Server startup

This is where Apache reads its configuration directives and merges them into instructions for how to handle requests, including overriding the instructions further at request time.

Child startup

Apache operates with a pool of pre-forked processes that handle the incoming requests in parallel.