is_favicon() │ WP 5.4.0

Checks if the current request is a request for the favicon.ico file.

This function is called by default when loading the site template page in the file wp-includes/template-loader.php

The earliest moment this function can be called is the hooks: parse_query, wp, template_redirect or later.

See also the hook do_favicon.

The function will trigger when the URL /favicon.ico is requested

This usually happens automatically when the site loads to display the tab icon:

  • A regular user visit to the site — the browser itself makes a request to /favicon.ico.
  • A bot (for example, a search engine) indexes the site and requests the icon.
  • A direct link like https://example.com/favicon.ico.

The function may not trigger if:

  • The favicon is requested via a different path (for example, specified in the meta tag <link rel="icon" href="https://example.com/custom-icon.ico">).
  • The request bypasses WordPress — for example, if the server (Nginx/Apache) serves favicon.ico directly, bypassing index.php.
  • Server-level caching (Nginx, Varnish, ...) is used, and the favicon is served without WP involvement.
  • WP is installed in a subdirectory, and the favicon is requested from the root (/favicon.ico), where WP is not present.

  • A separate domain or CDN is used for static files, and the icon is loaded from there.

  • WP initialization is intercepted, for example, via auto_prepend_file — this is a PHP directive that allows including a file before executing any other PHP code.

    Example in php.ini or .htaccess:

    php_value auto_prepend_file /path/to/file.php

    If the following condition is set in this file, then WP will not load at all when requesting /favicon.ico:

    if ( $_SERVER['REQUEST_URI'] === '/favicon.ico' ) {
	readfile( '/path/to/favicon.ico' );
	exit;
}
Uses: WP_Query::is_favicon()

No Hooks.

Returns

true|false. Whether the favicon.ico file is requested.

Usage

if( is_favicon() ){
	// do staff
}

Examples

0

#1 Generating an icon on the fly

This code will return its favicon.ico and terminate execution when the browser requests /favicon.ico.

The icon is generated on the fly using GD and output as a favicon (16x16, black-and-white pattern):

add_action( 'do_favicon', 'get_simple_favicon' );

function get_simple_favicon() {

	header( 'Content-Type: image/x-icon' );

	$size = 16;
	$img  = imagecreatetruecolor( $size, $size );

	$white = imagecolorallocate( $img, 255, 255, 255 );
	$black = imagecolorallocate( $img, 0, 0, 0 );

	// Drawing a simple checkerboard pattern
	for ( $y = 0; $y < $size; $y++ ) {
		for ( $x = 0; $x < $size; $x++ ) {
			$color = ( ( $x + $y ) % 2 === 0 ) ? $black : $white;
			imagesetpixel( $img, $x, $y, $color );
		}
	}

	// Saving the image .ico to a variable
	ob_start();
	imagepng( $img );
	imagedestroy( $img );
	$png_data = ob_get_clean();

	// Outputting to the screen (converting PNG to ICO via header)
	echo $png_data;

	exit;
}
0

#2 Examples of using the is_favicon() function

Although this function is used automatically in WP in the file wp-includes/template-loader.php, it can still be useful at times.

For example, we want to log all favicon requests separately:

if ( is_favicon() ) {
	error_log( 'Favicon requested: ' . $_SERVER['REMOTE_ADDR'] );
}

Notes

  • Global. WP_Query. $wp_query WordPress Query object.

Changelog

Since 5.4.0 Introduced.

is_favicon() code WP 7.0

wp-includes/query.php 
function is_favicon() {
	global $wp_query;

	if ( ! isset( $wp_query ) ) {
		_doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
		return false;
	}

	return $wp_query->is_favicon();
}

Conditional tags (all)

Theme files connection