3 Plugins For Easy Debugging

Essential Debugging Plugins

Running a marketplace can be complicated and takes time to learn. This post will outline 3 essential plugins that we use and recommend. Being able to effectively debug WordPress and WooCommerce sites can save you a lot of time and money. Having your staging environment configured will make this debugging even easier.

These are plugins that we install and use on a daily basis both locally and when providing pro support for WC Vendors Pro and our other paid add-ons. You should use when debugging various aspects of your multi-vendor marketplace.

User Switching

There are times that you will need to switch to another user quickly. You may have a vendor contact you and report a problem. It could be with their dashboard or some other view that they see which you usually wouldn’t. This includes being able to switch to a customers view and work out an issue they may be having.

It’s very easy to use. All you have to do is log in to your WordPress admin dashboard. Navigate to Users and find the user you want to switch to and click on the ‘switch to’ link. Once you have done this, you will assume a session on your site that is the same as that the user sees.

Query Monitor Plugin

Being able to easily switch users without changing passwords or modifying an account can save you a lot of time. We have been using this plugin since we first started providing support and cannot recommend it enough.

Query Monitor

Query Monitor is a valuable WordPress debugging tool that can help shed light on slowdowns in your site. Both within the WordPress administration as well as your customer-facing site.

Query Monitor is the developer tools panel for WordPress. It enables debugging of database queries, PHP errors, hooks and actions, block editor blocks, enqueued scripts and stylesheets, HTTP API calls, and more.


We use and recommend Query Monitor to our users when they are debugging complex sites. There might be a slow query or some internal error that is being missed. Query Monitor will highlight the bottlenecks in your system. We use it to debug our own plugins as well as conflicts and slowdowns from other plugins.

Plugins query

After you have installed Query Monitor you will get a new admin menu bar item that provides detailed statistics about everything that happens on every page load. You can find such metrics as

  • slow queries
  • fatal errors
  • templates that are loaded
  • plugin order
  • and so much more.

Query Monitor has helped find poorly written plugins or bugs in our code that we otherwise wouldn’t have been able to find on customer sites. It is one of the best tools we found to debug internal performance issues. Unlike P3 Profile plugin (which you should never use) Query Monitor actually finds measurable problems.

Once you have completed your debugging we advise that you disable the plugin or completely remove it and only have it installed on your staging site. The plugin can add a bit of overhead to your page loads so use it sparingly on your production website.

WP Mail Logging by Mail Poet

Email sending issues is a common problem with WordPress sites. Once you add a few more plugins that require emails then it can get quite difficult to work out what is happening with your outgoing mail. WP Mail Logging is a plugin that logs all outgoing emails so that you can see if the email has been triggered. This does not mean that the email has actually sent. All it means is that WordPress and the plugin you’re debugging has triggered the email.

We often have users contact us and tell us that their email isn’t sending and most of the time its not actually a problem with our products but a problem with either a mail conflict or mail configuration in general.

WP Mail Logging makes it very easy to see which emails are sending. After you install the plugin all you have to do is go to Tools > Mail log in the WordPress admin. From here you can see if the email is triggered by your site.

WP Mail Logging

If it is then you know either the email isn’t being delivered or is going to spam. If other WordPress emails are being delivered then it could be a plugin conflict or it could mean a problem with your mail server. You can also use this to view what the email looks like so if you have any display issues, WP Mail Logging is great for debugging this too.

Once you have figured out the issue with your email you can use the plugin to resend the emails if you need to. So if you ever have an issue with your email, be sure to install this plugin and check it. If you want to keep the mail log running we advise that you ensure your settings are cleaning the logs on a regular basis. Seven days is usually the right amount for a medium-sized site.


These 3 plugins are essential in your debugging and maintenance regime. You should install and use these plugins so that you can get familiar with them. If you have ever had an issue with your WordPress site and haven’t been able to figure it out, chances are one of these 3 plugins would help solve it.

We often ask our users to install these plugins to debug issues so we recommend you get to know them. It’ll save you time and money.

Jamie is the founder and lead developer of WC Vendors. He has been working in the WordPress, WooCommerce and Marketplace space for more than 15 years, 9 of those dedicated to multivendor marketplaces.