Programmatically add a redirect to the Yoast SEO Premium redirects.

add-yoast-redirect.php

<?php
/**
 * Create a new redirect within the Yoast redirect system.
 *
 * @param string $origin_url      redirecting from.
 * @param string $destination_url redirecting to.
 * @param int    $type            redirect code, defaults to 301.
 * @param string $format          the format, either 'plain' or 'regex', defaults to 'plain'.
 * @return void
 */
function add_yoast_redirect( $origin_url, $destination_url, $type = 301, $format = 'plain' ) {

	$redirect_option = new WPSEO_Redirect_Option();

	$redirect_array = array(
		'origin' => $origin_url,
		'url'    => $destination_url,
		'type'   => $type,
		'format' => $format,
	);
	
	// Add the redirect to Yoast SEO table.
	$redirect_object = new WPSEO_Redirect( $redirect_array['origin'], $redirect_array['url'], $redirect_array['type'], $redirect_array['format'] );
	$redirect_option->add( $redirect_object );
	$redirect_option->save();
	
	// Apply the redirect.
	$manager = new WPSEO_Redirect_Manager();
	$manager->export_redirects();

}

A few changes to make in order to make things work:

1. change 'origin' => $redirect_url, to 'origin' => $orgin_url, line 16 (or $origin_url with an 'i', but then also change it in the function declaration)
2. With this code, redirects are well placed in the table in the Yoast plugin, but are not applied. You need to add the following after the save() method :
   $manager = new WPSEO_Redirect_Manager();
$manager->export_redirects();

Hey @fluktegrute thanks so much for the feedback! I've updated the function above accordingly.