When your WordPress website starts showing unexpected behavior blank pages, plugin errors, or theme issues troubleshooting can become frustrating if you don’t know where to start. That’s where the debug.log file becomes a powerful tool.

In this article, we’ll break down what the debug.log file is, how to enable it, where to find it, and how to use it effectively to diagnose and fix common WordPress problems.

What is the debug.log File in WordPress?

The debug.log file is a part of WordPress’s built-in debugging system. It captures and records PHP errors, warnings, and notices that occur during the operation of your website. Instead of displaying these messages on your site (which can be a security risk), they are saved in a log file for review.

This file is essential for:

• Identifying plugin or theme conflicts

• Catching deprecated functions

• Troubleshooting fatal errors

• Debugging custom code issues

Why is debug.log Important?

Many WordPress problems are invisible to the average user. For example, a plugin may silently fail, or a function may trigger errors only in specific scenarios. The debug.log acts like a behind-the-scenes diary of what’s going wrong, so you can fix issues without guessing.

Some benefits include:

• Non-intrusive debugging: Errors are logged discreetly, without affecting the front end.

• Time-saving: It narrows down problems quickly by showing file paths, line numbers, and error types.

• Essential for developers and advanced users: It gives detailed insights into how WordPress and your code behave.

How to Enable debug.log in WordPress

You don’t need a plugin to activate the debug.log file. Just access your site’s root directory via File Manager (in your hosting control panel) or through FTP. Follow these steps:

Step 1: Locate the wp-config.php File

This file is located in the root directory of your WordPress installation (the same place where wp-admin, wp-content, and wp-includes folders are found).

Step 2: Add Debugging Code

Open wp-config.php and scroll near the bottom, just above this line:

Add the following code:

What These Lines Do:

• WP_DEBUG enables debugging mode.

• WP_DEBUG_LOG stores errors in a file called debug.log under /wp-content/.

• WP_DEBUG_DISPLAY set to false hides errors from being shown on the website frontend.

• @ini_set() ensures PHP doesn’t display errors directly in the browser.

Where to Find the debug.log File

Once enabled and an error occurs, WordPress will automatically create the file at this location:

You can open it using a text editor or directly from your hosting File Manager. New error messages will be appended as they happen.

How to Use debug.log for Troubleshooting

Let’s look at how this log helps in real-world issues:

1. Plugin or Theme Conflicts

If activating a plugin breaks your site, check debug.log. You’ll often find a message like:

This tells you exactly which plugin and line caused the problem.

2. Deprecated or Broken Functions

You might see:

This doesn’t break your site but is a warning that your theme or plugin is using outdated functions that may cause issues in the future.

3. Database or File Permission Errors

You may notice:

4. Custom Code Errors

If you’ve added custom code snippets or edited a theme’s functions.php, debug.log will help you identify syntax or logic errors.

Best Practices While Using debug.log

• Don’t leave debugging enabled on a live site for too long. Once the issue is resolved, disable it by setting WP_DEBUG to false.

• Regularly clear the debug.log file to avoid clutter. You can delete it manually; it will regenerate if errors occur again.

• Avoid displaying errors on the frontend on production sites it exposes technical details to users and potential attackers.

• Use it on staging environments if you’re doing major theme or plugin development/testing.

How to Disable Debug Mode

Once you’ve finished troubleshooting, edit your wp-config.php and either:

• Delete the debug lines, or

• Set WP_DEBUG back to false like this:

This turns off logging and error capturing.

Conclusion

The debug.log file is a valuable asset for WordPress troubleshooting. Whether you’re a site owner, webmaster, or advanced user, knowing how to enable and read this file can save time, prevent site crashes, and help you communicate more effectively with support or developers.

By learning to use the debug.log, you can take control of your site’s stability and performance without relying on guesswork.

FAQs

1. Is it safe to keep debug.log enabled all the time?
No. It’s best to enable it only when troubleshooting. Keeping it on may expose sensitive paths or functions in the log.

2. Can visitors see the debug.log file?
Generally, no. But ensure your /wp-content/ directory doesn’t allow direct file browsing.

3. Does enabling debug mode slow down the site?
Slightly, yes. Writing logs adds a small performance cost, which is why it should be disabled in production.

4. What if debug.log doesn’t appear?
Make sure the /wp-content/ folder is writable and errors are actually occurring.

5. Can I use a plugin instead?
Yes, there are plugins like “Error Log Monitor” that can help, but manual control is more precise.

6. Will this help with white screen errors?
Absolutely. These often result from fatal PHP errors that debug.log can reveal.

7. Is debug.log created in multisite WordPress?
Yes, the same file under /wp-content/ serves all sites in the network.

8. How big can the debug.log file get?
It can grow large over time. Delete or archive it regularly to maintain site performance.

9. Should I send the debug.log to support teams?
Yes. Sharing logs can help your hosting provider or developer pinpoint problems quickly.

10. Can I disable debug.log without editing code?
Not without a plugin. Editing wp-config.php is the standard way.