Filters and example code for Yoast SEO sitemaps

yoast_seo_sitemap_add_custom_type.php

<?php
/********* DO NOT COPY THE PARTS ABOVE THIS LINE *********/

/* Create a Yoast SEO sitemap for a custom post type
 * Credit: Team Yoast
 * Last Tested: Unknown
 * Documentation: https://developer.yoast.com/features/xml-sitemaps/api/#add-a-custom-post-type
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
 * HOW TO USE
 * Replace TYPE with your custom type
 */

add_action('init', 'enable_custom_sitemap');

function enable_custom_sitemap()
{
  global $wpseo_sitemaps;
  if (isset($wpseo_sitemaps) && !empty($wpseo_sitemaps)) {
    $wpseo_sitemaps->register_sitemap('TYPE', 'create_TYPE_sitemap');
  }
}

yoast_seo_sitemap_add_external.php

<?php
/********* DO NOT COPY THE PARTS ABOVE THIS LINE *********/

/* Add External Sitemap to Yoast Sitemap Index
* Credit: Paul https://wordpress.org/support/users/paulmighty/
* Modified by: Team Yoast
* Last Tested: Aug 25 2017 using Yoast SEO 5.3.2 on WordPress 4.8.1
* Documentation:
* https://developer.yoast.com/features/xml-sitemaps/api/#add-additionalexternal-xml-sitemaps-to-the-xml-sitemap-index
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
* This code adds two external sitemaps and must be modified before using.
* Replace http://www.example.com/external-sitemap-#.xml with your external sitemap URL.
* Replace 2017-05-22T23:12:27+00:00 with the time and date your external sitemap was last updated.
* Format: yyyy-MM-dd'T'HH:mm:ssZ
* If you have more/less sitemaps, add/remove the additional section.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
* Please note that changes will be applied upon next sitemap update.
* To manually refresh the sitemap, please disable and enable the sitemaps.
*/

add_filter('wpseo_sitemap_index', 'add_sitemap_custom_items');

function add_sitemap_custom_items($sitemap_custom_items)
{
  $sitemap_custom_items .= '
<sitemap>
<loc>http://www.example.com/external-sitemap-1.xml</loc>
<lastmod>2017-05-22T23:12:27+00:00</lastmod>
</sitemap>';

  /* Add Additional Sitemap
   * This section can be removed or reused as needed
   */
  $sitemap_custom_items .= '
<sitemap>
<loc>http://www.example.com/external-sitemap-2.xml</loc>
<lastmod>2017-05-22T23:12:27+00:00</lastmod>
</sitemap>';

  /* DO NOT REMOVE ANYTHING BELOW THIS LINE
   * Send the information to Yoast SEO
   */
  return $sitemap_custom_items;
}

yoast_seo_sitemap_add_image.php

<?php
/********* DO NOT COPY THE PARTS ABOVE THIS LINE *********/

/* Add single image to all content items in the Yoast SEO sitemap
 * Credit: Yoast team
 * Documentation: https://developer.yoast.com/features/xml-sitemaps/api/
 * Last Tested: Aug 08 2024 using Yoast SEO 23.2 on WordPress 6.6.1
 */

function filter_wpseo_sitemap_urlimages( $images ) {
  array_push( $images, [ 'src' => 'https://www.example.com/wp-content/uploads/extra-image.jpg' ]);
  return $images;
};

add_filter( 'wpseo_sitemap_urlimages', 'filter_wpseo_sitemap_urlimages' ); // Post Types (posts, pages, custom post)
add_filter( 'wpseo_sitemap_urlimages_term', 'filter_wpseo_sitemap_urlimages' ); // Taxonomies (category, tags)

yoast_seo_sitemap_change_entries_per_page.php

<?php
/********* DO NOT COPY THE PARTS ABOVE THIS LINE *********/

/* Change the number of entries per sitemap
 * Credit: Yoast Team
 * Last Tested: Oct 17 2018 using Yoast SEO 8.4 on WordPress 4.9.8
 * Limit should be either lower than 100 or a multiple of 100 to avoid problems with the sitemap pagination
 * Documentation: https://developer.yoast.com/features/xml-sitemaps/api/#alter-the-number-of-sitemap-entries
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
 */

add_filter('wpseo_sitemap_entries_per_page', 'max_entries_per_sitemap');

function max_entries_per_sitemap() {
  return 10;
}

yoast_seo_sitemap_remove_homepage.php

<?php
/********* DO NOT COPY THE PARTS ABOVE THIS LINE *********/

/* Remove homepage from the page sitemap
 * Credit: Yoast team
 * Last Tested:  Jun 20 2024 using Yoast SEO 22.9 on WordPress 6.5.4
 */

add_filter( 'wpseo_sitemap_url', function ( $output, $url ) {
	if ( $url['loc']  === home_url( '/' ) ) {
		return '';
	}

	return $output;
}, 10, 2 );

yoast_seo_sitemap_remove_images.php

<?php
/********* DO NOT COPY THE PARTS ABOVE THIS LINE *********/

/* Remove all image URLs for the Yoast SEO sitemap
 * Credit: Yoast team
 * Last Tested: Aug 08 2024 using Yoast SEO 23.2 on WordPress 6.6.1
 */

// Post Types (posts, pages, custom post types)
add_filter( 'wpseo_sitemap_urlimages', '__return_empty_array' );

// Taxonomies (category, tags)
add_filter( 'wpseo_sitemap_urlimages_term', '__return_empty_array' );

// use this in functions.php to add custom sitemap in Yoast index_sitemap.xml
add_filter('wpseo_sitemap_index', 'add_sitemap_custom_items');

function add_sitemap_custom_items($sitemap_custom_items)
{
    $site_url = home_url();
    $lastmod = date('c');
    $sitemap_custom_items .= '
    <sitemap>
        <loc>' . esc_url($site_url) . '/folder-name/sitemap.xml</loc>
        <lastmod>' . esc_html($lastmod) . '</lastmod>
    </sitemap>';
    
    return $sitemap_custom_items;
}