Debug PHP applicationsUltimate

Last modified: 08 March 2021

warning

The following is only valid when the PHP plugin is installed and enabled.

This section provides a handful selection of tutorials that will help you get started with PHP debugging in IntelliJ IDEA.

Quick Start

Before proceeding with any of the debugging scenarios, you need to choose a debugging engine and install it in your PHP environment. These tutorials will guide you through the installation process:

Install Xdebug (recommended)Install Zend Debugger

With the debugging engine installed, you can start debugging by following the zero-configuration debugging approach:

  1. Choose and install the browser extension suitable for your browser.

  2. On the IntelliJ IDEA toolbar, toggle the Start Listening for PHP Debug Connections button to start listening for incoming PHP debug connections, or choose Run | Start Listening for PHP Debug Connections from the main menu.

  3. Set a breakpoint in your code. Breakpoints can be set in the PHP context inside PHP, HTML, TWIG, BLADE, and files of other types. Line breakpoints can be set only on executable lines, but not on comments, declarations, or empty lines. For details on getting started with Twig and Blade debugging, refer to Debug Twig templates and Debug Blade templates.

  4. Start the debugging session in the browser using the installed browser extension.

  5. During a debugging session, examine the program state: see variable values, evaluate expressions, step through the program, and so on.

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See Zero-configuration debugging for the detailed step-by-step instructions, and Advanced debugging scenarios for more debugging scenarios.

Debugging a PHP web application

Depending on your environment, you can debug your PHP Web application locally or remotely.

Local debuggingRemote debugging
The debugging engine and IntelliJ IDEA are running on the same machine.The debugging engine is running on a remote environment (for example, a remote server or a virtual machine).
Follow the Zero-configuration debugging procedure.

  • If you can establish direct connection between your machine and the remote server, that is, no firewall, router or ISP is blocking the connection from your remote server to the specific port on the local machine, follow the Zero-configuration debugging procedure.

  • Otherwise, if direct connection cannot be established, follow the Remote debugging via SSH tunnel procedure.

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To test direct connection, run the telnet host 9000 (for Xdebug) or the telnet host 10137 (for Zend Debugger) command on the remote server and ensure that connection is established. Here, host is the IP address of the local machine IntelliJ IDEA is running on.

To check for opened inbound ports, you can use canyouseeme.org or a similar service.

Debugging a PHP CLI script

Depending on your environment, you can debug your PHP CLI script locally or remotely.

Local debuggingRemote debugging
The debugging engine and IntelliJ IDEA are running on the same machine.The debugging engine is running on a remote environment (for example, a remote server or a virtual machine).
Follow the Debug a PHP CLI script procedure.

  1. Set up a remote PHP interpreter as described in Configuring Remote PHP Interpreters.

  2. Follow the Debug a PHP CLI script procedure.

Troubleshooting

When using Xdebug or Zend Debugger with IntelliJ IDEA, some misconfiguration can prevent the debugger from working. In the Troubleshooting guide, you will find the description of some common issues and learn how to troubleshoot them.

Advanced debugging scenarios

The following topics will assist you in exploring the advanced debugging scenarios in IntelliJ IDEA:

See also

Concepts

Profiling

JavaScript Support