Pross

<?php
add_action( 'user_register', 'add_user_to_sendy_list' );

function add_user_to_sendy_list( $user_id ) {
  $list = 'SENDY_LIST_ID';
  $url  = 'http://SENDY_INSTALL_URL/subscribe';
  $user = get_userdata( $user_id );
  
  $email = $user->data->user_email;
  $name  = $user->data->user_nicename;