One of the most commonly asked questions when I discuss WordPress development is how to efficiently perform AJAX requests from within the WordPress environment. We will discuss: 1) How and why performing AJAX in WordPress is a bit tricky 2) The old way of working with AJAX in WP 3) The new and better way to use AJAX in WP using the WP REST API added to core in 4.7 4) What to consider when converting plugins from the old AJAX method to the new standardized one 5) Some examples of cool and common use cases for AJAX in WordPress.