What are WordPress Hooks? - Action and Filter

Wordpress is a more powerful and user friendly platform to work. But If you need to be a master in that, then you should know how it works in the backend. If you’ve started learning WordPress development, you’ll hear one word again and again: Hooks. At first, it sounds technical and confusing, but once you understand the idea, hooks actually make WordPress development much easier and more powerful.

In this beginner-friendly guide, we’ll break down what hooks are, why they exist, and how you can start using them in your own projects.

What Are Hooks?

In simple terms, hooks allow you to change or add functionality in WordPress without modifying the core files.

WordPress provides predefined points where developers can “hook” their own code.

Think of it like this:

WordPress runs thousands of functions while loading a page. Hooks allow you to insert your own function at a specific moment during that process.

This is one of the main reasons developers love working with WordPress.

Why Hooks Are Important

Hooks make WordPress flexible and safe to customize.

What if the hooks do not exist, then developers would have to edit WordPress core files, which makes a huge mistake and leads to collapse of the entire website and whenever the update comes it flush all your changes by overriding it.

Hooks allow you to:

• Add new features
• Modify existing behavior
• Extend plugins and themes
• Keep your site update-safe

Types of WordPress Hooks

WordPress mainly provides two types of hooks.

1. Action Hooks

Action hooks allow you to run custom code at a specific point in WordPress execution. They simply perform the task or do something without returning anything.

Example uses:

• Add content after a blog post
• Load custom scripts
• Send notifications
• Modify admin dashboard behavior

Basic Syntax

add_action('hook_name', 'your_function_name');

Example:

function my_custom_message() {

   echo "<p>Thanks for reading this blog!</p>";

}

add_action('wp_footer', 'my_custom_message');

What happens here?

When WordPress loads the footer, it runs the function my_custom_message() and prints the message to the footer.

2. Filter Hooks

Filter hooks allow you to modify existing content before it is displayed.

Unlike actions, filters must return a value.

Basic Syntax

add_filter('hook_name', 'your_function_name');

Example:

function add_text_to_post($content) {

   $content .= "<p>Thanks for visiting our blog!</p>";

   return $content;

}

add_filter('the_content', 'add_text_to_post');

What happens here?

WordPress passes the post content to your function, your function modifies it, and then returns the updated content.

Difference Between Action and Filter

Feature	Action Hook	Filter Hook
Purpose	Used to execute custom code at a specific point	Used to modify or change existing data
Return Value	Not required	Required (must return the modified value)
Main Function	add_action()	add_filter()
Data Modification	Cannot modify data directly	Used specifically to modify data
Example Hook	wp_footer, init, wp_head	the_content, the_title, the_excerpt
Usage Scenario	Add scripts, display messages, run functions	Change post content, modify titles, edit output
Example Code	add_action('wp_footer','my_function');	add_filter('the_content','my_function');

Common Hooks Every Beginner Should Know

Here are some popular hooks used by developers:

Hook	Purpose
wp_head	Add code to website header
wp_footer	Add code to footer
the_content	Modify post content
init	Run code when WordPress initializes
wp_enqueue_scripts	Load scripts and styles

Real Example: Add Word Count to Posts

Let’s create a simple filter that adds word count to every blog post.

function web_display_reading_time($content) {

    if (is_single() && is_main_query()) {

        // Count words in post

        $word_count = str_word_count(strip_tags($content));

        // Average reading speed

        $reading_speed = 200;

        // Calculate reading time

        $reading_time = ceil($word_count / $reading_speed);

        // Display message

        $reading_time_html = "<p><strong>Estimated Reading Time:</strong> " . $reading_time . " min</p>";

        // Add before post content

        $content = $reading_time_html . $content;

    }

    return $content;

}

add_filter('the_content', 'web_display_reading_time');

What this code does:

1. Calculates the total word count of each blog
2. Divides total word count by reading speed
3. Display Reading time before the post content

Simple but powerful.

Where Should You Use Hooks?

Hooks can be used in:

• Theme functions.php
• Custom plugins
• Child themes

However, if you’re building reusable features, it's best to create a custom plugin instead of adding everything to the theme.

Best Way to Learn Hooks

The best way to understand hooks is practice.

Start with small customizations like:

• Adding text after posts
• Showing estimated reading time
• Creating custom admin messages
• Displaying post views

As you experiment, you’ll see how flexible hooks really are.

Final Thoughts

WordPress Hooks are the backbone structure of the entire website. Once you understand how they work, you can modify almost any behavior without touching the core system.

Whether you're developing themes, plugins, or simply customizing a website, mastering hooks will make your work much more efficient.

If you're serious about WordPress development, learning hooks is one of the most important skills you can build while working with WordPress.