AJAX stands for Asynchronous JavaScript and XML. It’s a technique that lets a webpage fetch or send data in the background — without reloading the entire page.
You’ve almost certainly experienced this without realizing it. When you type into a live search box and results appear instantly, or when you “like” a post and the counter updates without a page refresh, AJAX is usually behind it.
Why It’s Called That
The name is a bit outdated — modern AJAX requests almost always use JSON instead of XML for the data format — but the term stuck around anyway. The important word is “asynchronous,” meaning the page keeps working while the request happens in the background.
AJAX in WordPress
WordPress has built-in support for AJAX requests through a dedicated endpoint, which plugins commonly use for things like live comment submissions, dynamic filtering, or auto-saving drafts while you write.
If you notice a page updating smoothly without a visible reload, there’s a good chance AJAX is quietly doing the work behind the scenes.