Query Monitor is a comprehensive debugging plugin for WordPress and WooCommerce that offers real‑time insights into nearly every aspect of your site’s backend. Accessible via the admin toolbar, it tracks database queries (highlighting slow, duplicate, or erroneous ones), PHP errors and deprecation notices, HTTP API calls, enqueued scripts/styles (with dependency checks), AJAX and REST API events, user capability checks, template loading paths, rewrite rules, block editor usage, environment info, transients, multisite actions, and redirects (including call‑stack headers). It organizes data by plugin, theme, and function to help you pinpoint performance bottlenecks and coding issues efficiently—making it an essential tool for developers focused on optimization and debugging .