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Limitations

WordPress Playground has a few limitations that you should be aware of.

If you are a user​

You can't access the Plugins or Themes Directory in the browser​

The web version of WordPress does not support network connections, so the plugin directory in wp-admin is not available. However, you can still upload plugins and open them with "?plugin=coblocks" or a similar query string.

You can track the progress of adding network support in the browser at https://github.com/WordPress/wordpress-playground/issues/85.

When you refresh the page, you'll lose anything you did (unless you export it)​

In the web version of WordPress Playground, all database changes and uploads are gone once the page is refreshed. Preserving them would be useful for courses, technical demos, even sharing a link to your changes.

Be sure to export your work before you close the page.

You can track the progress of support for persisting the changes at https://github.com/WordPress/wordpress-playground/issues/19

If you are a developer​

Iframe quirks​

WordPress is rendered in an iframe, which makes it hard to correctly handle target="_top" in links. This means that clicking on <a target="_top">Click here</a> may reload the main browser tab.

Also, JavaScript popup windows originating in the iframe may not be displayed in certain cases.

Pthreads Support​

The WebAssembly version of PHP is built without pthreads support, which means you cannot use pcntl_ functions like pcntl_fork() or pcntl_exec(). Most of the time, you don't need them, but there are a few WP-CLI commands and a few corner-cases in PHPUnit tests that use them.

You can track the progress of adding pthreads support at https://github.com/WordPress/wordpress-playground/issues/347.

XDebug Support​

XDebug is not supported in the WebAssembly version of PHP. You can track the progress of adding XDebug support at https://github.com/WordPress/wordpress-playground/issues/314.

Fibers​

Fibers are a PHP 8.1+ feature that is currently unsupported in Playground. See https://github.com/WordPress/wordpress-playground/blob/9065025043209ce06c9540886567ca5bc0ccfb11/packages/php-wasm/compile/Dockerfile#L484-L493 for more information.