We work on a lot of WordPress sites here at WP Kite all around the world and as you probabily already know, WordPress powers over 40% of all websites on the internet, making it the most popular content management system (CMS) worldwide.
Its flexibility and extensive plugin ecosystem allow users to create virtually any type of website. However, with great flexibility comes complexity, and even seasoned developers can run into issues that require debugging. Whether it’s a plugin conflict, a theme error, or a mysterious slowdown, having the right debugging tools is essential.
Debugging in WordPress can be a daunting task, especially if you’re not sure where to start. While WordPress has built-in debugging features, they may not provide the depth of information needed to diagnose complex issues. Fortunately, there are several debug plugins available that can help you identify and resolve problems efficiently.
In this article, we’ll explore the best debug plugins for WordPress which we typically use when we get a client request to help them with an issue, discussing their features, pros and cons, and ideal use cases to help you choose the right tool for your needs.
1. Query Monitor
Overview
Query Monitor is one of the most comprehensive debugging plugins available for WordPress. It provides detailed information about database queries, PHP errors, hooks, conditionals, scripts, styles, and more. It’s an essential tool for developers who need in-depth insights into what’s happening behind the scenes.
Key Features
- Database Queries: View all database queries executed on the current request, including the query type, component, and calling function. It highlights slow queries and duplicates.
- PHP Errors: Captures and displays notices, warnings, and deprecated functions.
- Scripts and Styles: Lists enqueued scripts and styles along with their dependencies.
- HTTP API Calls: Monitors outgoing HTTP requests.
- Ajax and REST API: Provides debugging information for Ajax calls and REST API requests.
- Blocks and Gutenberg: Offers support for debugging block-related issues in the Gutenberg editor.
- Multisite Support: Works seamlessly in multisite environments.
Pros
- Comprehensive Information: Offers a wide range of debugging data in one place.
- User-Friendly Interface: Integrates with the WordPress admin bar for easy access.
- Performance Profiling: Helps identify performance bottlenecks.
- Extensibility: Developers can extend its functionality through hooks and filters.
Cons
- Resource Intensive: May consume significant server resources, so it’s best used in development environments.
- Complexity: The vast amount of data can be overwhelming for beginners.
Best For
Developers and advanced users who need detailed insights to diagnose complex issues, optimize performance, and debug custom code.
2. Debug Bar
Overview
Debug Bar adds a debug menu to the WordPress admin bar, displaying useful debugging information. It’s a lightweight tool that provides quick access to cache status, query information, and other helpful data.
Key Features
- WP_Query Object: Displays the current query object and template information.
- Database Queries: Shows the number of queries and execution time.
- PHP Warnings and Notices: Captures and displays PHP errors.
- Cache Status: Provides information about the cache hits and misses.
- Extensions: Supports additional plugins like Debug Bar Console and Debug Bar Cron.
Pros
- Lightweight: Minimal impact on site performance.
- Easy to Use: Simple interface suitable for beginners.
- Extendable: Can be enhanced with extensions for more functionality.
Cons
- Limited Features: Doesn’t provide as much depth as Query Monitor.
- Basic UI: The interface is functional but less polished.
Best For
Users who need a straightforward debugging tool to access essential information without the complexity of more advanced plugins.
3. Health Check & Troubleshooting
Overview
Health Check & Troubleshooting is an official plugin developed by the WordPress community. It performs a series of checks to detect common configuration errors and known issues. The troubleshooting mode allows you to disable plugins and themes for your user session without affecting visitors.
Key Features
- Site Health Status: Provides a health check score and recommendations.
- Troubleshooting Mode: Safely deactivate plugins and switch themes to identify conflicts.
- Debug Information: Gathers technical details for support purposes.
- PHP Information: Displays PHP settings and configurations.
Pros
- Safe Troubleshooting: Isolate issues without impacting site visitors.
- User-Friendly: Suitable for all skill levels.
- Official Support: Backed by the WordPress community.
Cons
- Limited Debugging Data: Not as detailed as other debugging tools.
- No Performance Metrics: Doesn’t provide insights into performance bottlenecks.
Best For
Site administrators and non-developers who need to diagnose common issues and conflicts in a safe environment.
4. WP Debugging
Overview
WP Debugging simplifies the process of enabling WordPress debugging constants without manually editing the wp-config.php file. It’s ideal for users who need to turn on debugging features temporarily.
Key Features
- Automatic Debugging: Activates
WP_DEBUG,WP_DEBUG_LOG, andSAVEQUERIES. - Debug Log: Stores errors and warnings in a debug.log file.
- Integration: Works well with other debugging tools.
Pros
- Convenient: Eliminates the need to edit configuration files.
- Safe: Ensures debugging is only active when needed.
Cons
- Limited Functionality: Doesn’t provide a user interface for viewing debug data.
- Requires Access to Files: You need to access the debug.log file via FTP or hosting control panel.
Best For
Users who need a quick and easy way to enable WordPress debugging features without manual configuration.
5. Log Deprecated Notices
Overview
Log Deprecated Notices helps developers identify deprecated functions and files in WordPress. This is crucial for maintaining compatibility with the latest WordPress versions.
Key Features
- Deprecated Functions: Logs usage of deprecated functions and files.
- Error Logging: Stores logs in a file for review.
- Compatibility Checks: Helps ensure themes and plugins are up-to-date with WordPress standards.
Pros
- Developer Focused: Essential for maintaining and updating custom code.
- Simple: Does one job well without unnecessary features.
Cons
- Narrow Scope: Only tracks deprecated notices.
- No Interface: Requires viewing log files directly.
Best For
Developers maintaining custom themes or plugins who need to ensure compatibility with the latest WordPress updates.
6. WP Log Viewer
Overview
WP Log Viewer allows you to view and manage your WordPress log files from the admin dashboard. It simplifies the process of monitoring logs without needing FTP access.
Key Features
- Log Management: View, search, and filter log entries.
- Custom Logs: Supports custom log files.
- Error Monitoring: Helps track errors and warnings.
Pros
- Convenient: Access logs directly from the dashboard.
- User-Friendly: Intuitive interface.
Cons
- Performance Impact: Large logs may slow down the admin area.
- Limited Debugging Tools: Focused on log viewing rather than comprehensive debugging.
Best For
Users who need an easy way to monitor logs without external tools.
7. Error Log Monitor
Overview
Error Log Monitor displays WordPress error logs in your dashboard. It provides real-time updates and alerts when new errors are logged.
Key Features
- Dashboard Widget: Shows recent errors at a glance.
- Email Notifications: Sends alerts when new errors occur.
- Customization: Set thresholds for notifications.
Pros
- Immediate Awareness: Quickly identify and respond to errors.
- Customizable Alerts: Control how and when you’re notified.
Cons
- Limited Scope: Only monitors error logs.
- Potential for Noise: May generate frequent notifications if not configured properly.
Best For
Site administrators who want to stay informed about errors without constantly checking logs.
8. Developer
Overview
Developer is a plugin designed to help developers optimize their development environment. It recommends tools and plugins based on your project type.
Key Features
- Environment Optimization: Ensures your setup is configured correctly.
- Plugin Recommendations: Suggests plugins for debugging, performance, and more.
- Best Practices: Encourages adherence to coding standards.
Pros
- Time-Saving: Quickly set up a robust development environment.
- Comprehensive: Addresses various aspects of development.
Cons
- Not a Direct Debug Tool: Doesn’t provide debugging features itself.
- Overkill for Non-Developers: Not necessary for casual users.
Best For
Developers setting up or refining their WordPress development environment.
9. Whoops Error Handler
Overview
Whoops Error Handler replaces the default WordPress error handler with the Whoops PHP error handler, providing detailed error information.
Key Features
- Enhanced Error Pages: Displays stack traces and code snippets.
- Detailed Error Information: Helps pinpoint the source of errors.
- Configuration Options: Customize how errors are displayed.
Pros
- In-Depth Insights: Makes debugging PHP errors easier.
- Modern Interface: Clear and informative error pages.
Cons
- Not for Production Sites: Should only be used in development environments.
- Technical: Requires understanding of PHP and error handling.
Best For
Developers needing detailed error information during development.
10. Simply Show Hooks
Overview
Simply Show Hooks helps developers see all the available hooks (actions and filters) on any page. It’s useful when customizing themes and plugins.
Key Features
- Hook Display: Shows hooks directly on the page.
- Contextual Information: Provides details about each hook.
- Frontend and Backend: Works on both admin and public pages.
Pros
- Customization Aid: Simplifies the process of finding the right hooks.
- Time-Saving: Reduces the need to search through documentation.
Cons
- Cluttered Display: Can overwhelm the page with information.
- Developer-Oriented: Not useful for non-coders.
Best For
Developers customizing WordPress themes or plugins who need quick access to hook information.
Comparison Table
| Plugin | Best For | Key Features | Ease of Use | Performance Impact |
|---|---|---|---|---|
| Query Monitor | Advanced debugging | Comprehensive data, performance profiling | Moderate | High |
| Debug Bar | Basic debugging | Essential info, extendable | Easy | Low |
| Health Check & Troubleshooting | Safe troubleshooting | Troubleshooting mode, site health | Easy | Low |
| WP Debugging | Enabling debugging constants | Automatic debugging activation | Easy | Low |
| Log Deprecated Notices | Updating code for compatibility | Logs deprecated functions | Moderate | Low |
| WP Log Viewer | Viewing logs in dashboard | Log management, error monitoring | Easy | Moderate |
| Error Log Monitor | Real-time error alerts | Dashboard widget, email notifications | Easy | Low |
| Developer | Setting up development environment | Tool recommendations, environment checks | Moderate | Low |
| Whoops Error Handler | Detailed PHP error handling | Enhanced error pages | Moderate | Moderate |
| Simply Show Hooks | Customizing themes/plugins | Displays hooks on pages | Moderate | Low |