WP Hooks Database, Resources & Tutorials for Plugin Developers

WordPress hooks let a plugin respond to events or change values without editing WordPress core. Start with the official Hooks handbook and the Code Reference: together they explain what a hook does, the arguments it receives, and where it runs.

Actions and filters do different jobs

An action calls your function at a particular point in execution. Use it for work such as registering a feature or enqueueing a resource. A filter receives a value that your function can change; return the value so WordPress can continue using it. Choosing a hook by name alone is risky: read its documentation and inspect the value or event it represents.

Find the right hook

1. Describe the change you need before searching. Changing an excerpt's length is different from rewriting its text or replacing an entire archive template.
2. Search the Code Reference for the relevant feature. Read the hook's parameters, return value where applicable, and source location.
3. Check whether it runs in the frontend, administration area, REST requests, or more than one context. A callback should not accidentally affect a different screen.
4. Check the documented introduction and change history against the WordPress versions your plugin supports.

A small filter example

This callback sets the automatic excerpt length to 35 words. Add it to a small site plugin on a staging site; do not edit a core file. It changes the length used by automatic excerpts, not manually written excerpts.

function wparena_example_excerpt_length( $length ) {
    return 35;
}
add_filter( 'excerpt_length', 'wparena_example_excerpt_length', 20 );

The third argument is the priority. Lower numbers run earlier; callbacks at the same priority run in registration order. If another callback later changes the value, it can override this result. The add_filter() reference explains priority and accepted arguments.

Build a plugin around the callback

The Plugin Handbook introduction covers the plugin file and header. Keep site functionality in a plugin when it should survive a theme change. Prefix functions to avoid naming collisions, and make the callback do only the work that belongs to the hook.

For actions, use add_action() and match the callback's parameters to the hook's documented arguments. Do not assume every action receives the current post or user.

Check permissions and test the result

A hook does not grant permission to modify data. For a privileged operation, check the user's capabilities. Where appropriate, also verify a nonce; a nonce is not a substitute for authentication or authorization.

Test the affected screen with the plugin active and inactive. Check logged-out visitors as well as the relevant user roles, inspect error logs, and confirm that unrelated pages retain their previous behavior. If the hook never runs, verify the request context and registration timing before changing priorities at random.