Display memory, page load time, average load time and query count in the footer of your site.
Simple loading text domains loading mapper
View debugging and performance information on database queries, hooks, conditionals, HTTP requests, redirects and more.
Displays and emails system information for debugging purposes for easy debugging of your own or a client/user site.
ManageWP is the ultimate WordPress productivity tool, allowing you to efficiently manage your websites.
WP Tota11y is an accessibility visualization toolkit.
A tool for experienced frontend performance engineers to take control over the scripts and styles enqueued on their site.
Checks plugins for deprecated WordPress functions, known security vulnerabilities and some unsafe PHP functions
Adminer is a full-featured MySQL management tool written in PHP. This plugin include this tool in WordPress.
Plugin Check is a validation tool for PHP developers (and a quality checker for end users) to locate undefined functions and methods.
Rollbar full-stack error tracking for WordPress
ZenCache is an advanced WordPress caching plugin inspired by simplicity. Speed up your site (BIG time!) with a reliable and fast WordPress cache.
A plugin to display your server's PHP info and WordPress environment data for debugging purposes.
Now it's easy to work with log files and folders on the WordPress server.
Logs each email sent by WordPress.
All-in-one bundle of essential plugins and functions for all WordPress websites.
Debug trace for WordPress, including action and filter tracing
Never accidentally send users emails from your testing sites again!
Quickly shows the template used for current page, number of queries, and execution time for PHP code.
Check your variables with Query Monitor
Intended for Developers: This template debugger helps you identify what template files are being used on the page you're viewing.
This plugin gives WordPress super admins an easy way to peek under the hood of the front-face of a WordPress installation via the admin bar.
Display prettified page source on the frontend.
Easily search, sort and group log entries. Click the log file with one click. See new errors automatically without refreshing.
Lists WordPress require() calls mainly for plugin code refactoring.
Admin page debugger tool
This plugin is intended for theme developers to use. It shows the current template being used to render the page, current post type, and much more.
List query-actions only for admins; for debug purposes
Reveal the theme template file used to render the displayed page, via the footer, widget, shortcode, and/or template tag.
Simple Debug Info Panel shows a little box on your site with helpful debugging info for developers: post/page ID, which template is being used, etc.