Filter Hook since 0.71

the_content

Filters post content before display

Description

the_content is the last chance to change post HTML before it reaches the template. Always return the string — filters that echo will break the page.

When it runs

When the_content() runs in a template. Default callbacks handle shortcodes and embeds by priority.

Signature

apply_filters( 'the_content', string $content );

Parameters

$content string — Post content HTML.

Examples

Basic

add_filter( 'the_content', function( $content ) {
    if ( is_single() ) {
        $content .= '<p><strong>Thanks for reading!</strong></p>';
    }
    return $content;
} );

Append a note on single posts. The original HTML is returned.

Real case

add_filter( 'the_content', function( $content ) {
    if ( has_shortcode( $content, 'gallery' ) ) {
        $content = '<div class="has-gallery">' . $content . '</div>';
    }
    return $content;
} );

Wrap posts that already contain a gallery shortcode.

Edge case

add_filter( 'the_content', function( $content ) {
    if ( is_admin() || wp_is_json_request() ) {
        return $content;
    }
    return $content;
} );

REST and admin can also run this filter — gate side effects.

Common Use Cases

Append/prepend content to posts
Transform shortcodes manually
Add schema markup to content
Strip or sanitize specific HTML

Common mistakes

Forgetting to return $content
Assuming $content is always plain HTML — block-editor posts include HTML comments like  around each block, which breaks naive string matching/regex written for classic-editor content.

Related hooks

Works with the_title
Alternative the_excerpt

FAQ

Why did my content disappear?

A the_content callback must return the string. Echoing instead of returning wipes the post body.

Why does the_content contain HTML comments like ?

Those are block delimiters the block editor saves into post_content. Each one already passed through the render_block filter before reaching the_content, so by the time your filter runs it's rendered HTML with block comments still attached — not raw block JSON.

Source: wp-includes/post-template.php

Group wizard

One session: this hook, then each related_hooks entry. Walk it and tell us what to change.

the_content → the_title → the_excerpt

functions.php — the_content

functions.php

<?php
/**
 * Practice: hook into the_content
 */
add_filter( 'the_content', function( $content ) {
	// Write your callback here. Always return the value.

	return $content;
} );

Group tour

the_content · Hook 1 of 3 · Step 1 of 7

Meet the_content

Filters post content before display

the_content is the last chance to change post HTML before it reaches the template. Always return the string — filters that echo will break the page.

type filterphase templatesince 0.71source wp-includes/post-template.php

apply_filters( 'the_content', string $content );

add_filter( 'the_content', function( $content ) {
    if ( is_single() ) {
        $content .= '<p><strong>Thanks for reading!</strong></p>';
    }
    return $content;
} );

PHP the_content · Hook 1 of 3 · Step 1 of 7

Practice the the_content WordPress filter hook in our interactive sandbox — a VS Code-style editor with a step-by-step the_content tutorial, add_filter exercises, and instant feedback. No local WordPress install required.