These are some invaluable plugins for debugging, developing, and monitoring WordPress sites.
Debugging Database Queries
See exactly what query WordPress is running. Great for debugging WordPress query problems in your code.
Similar to Debug This, but this has more emphasis on the WP queries on your site. Very useful.
A lifesaver if you don’t have database access for some reason. I don’t know how it works, but it brings up a real phpMyAdmin instance in a separate browser window. I used the first method, “Enter local phpMyAdmin” and that worked great!
Finding Fatal Errors
Most web monitoring services won’t inform you if your server is still working but your WordPress site has errors. This is a great plugin that sends you an email if it detects different types of WP errors and warnings that you can set. Note, however, that if you use an SMTP email plugin, and WordPress encounters a fatal error before that has time to load, you may not get informed if your server doesn’t send email. Shared hosting providers like Siteground usually have servers that send email. Other VPSs allow SMTP email setup at the server level which would also solve that problem.
Fatal errors are often caused by lack of RAM. This plugin displays how much RAM your site is using, along with PHP and WP limits. Very useful!
Debugging Your Theme
Checks your theme for anomalies.
Besides having the best name for a plugin ever, it’s a great development or diagnostic tool. Tells you which theme files are being used by any WordPress page so you can figure out which might be causing problems. Invaluable if you are doing template development or debugging! I install this on almost every site where I’m working on a custom theme or child theme.
Sadly, GoDaddy pulled the plug on the useful P3 Plugin Profiler plugin.
Switch any plugin or theme (from WordPress.org) to any other version with a few clicks!
Debugging User Account-Related Problems
This plugin lets you switch between users with a few clicks instead of having to log out, and log back in using a password. Super handy for debugging membership type of plugins where you need to jump around to users with different Roles.
Please leave your questions or comments below! – Brian