This does not use the API, but it’s a script I’ve used a hundred times over the years, always works. Simply drop it in the root of your install and then access the file directly. Remember to delete the file immediately afterward. I do not remember where I originally obtained this script.
<?php
// ADD NEW ADMIN USER TO WORDPRESS
// ----------------------------------
// Put this file in your WordPress root directory and run it from your browser.
// Delete it when you're done.
require_once('wp-blog-header.php');
require_once('wp-includes/registration.php');
// ----------------------------------------------------
// CONFIG VARIABLES
// Make sure that you set these before running the file.
$newusername="your_username";
$newpassword = 'youer_password';
$newemail="[email protected]";
// ----------------------------------------------------
// This is just a security precaution, to make sure the above "Config Variables"
// have been changed from their default values.
if ( $newpassword != 'YOURPASSWORD' &&
$newemail != '[email protected]' &&
$newusername !='YOURUSERNAME' )
{
// Check that user doesn't already exist
if ( !username_exists($newusername) && !email_exists($newemail) )
{
// Create user and set role to administrator
$user_id = wp_create_user( $newusername, $newpassword, $newemail);
if ( is_int($user_id) )
{
$wp_user_object = new WP_User($user_id);
$wp_user_object->set_role('administrator');
echo 'Successfully created new admin user. Now delete this file!';
}
else {
echo 'Error with wp_insert_user. No users were created.';
}
}
else {
echo 'This user or email already exists. Nothing was done.';
}
}
else {
echo 'Whoops, looks like you did not set a password, username, or email';
echo 'before running the script. Set these variables and try again.';
}