Synopsis: Request a page on a WordPress-powered website, and WordPress responds roughly as follows. Core libraries are loaded, followed by plugins. The URL is parsed to determine which items are being requested from the database, and a corresponding theme template is selected. The HTML is then rendered and sent to the browser.

When building client sites or advanced plugins, it’s often necessary to intervene in this process: to perform an early redirect, to modify the rules for parsing URLs, to load an alternate theme template. In this talk, I’ll outline some of the key places where you can (and where you shouldn’t!) interrupt and modify WordPress’s loading process for your purposes.