Purge Varnish on save action

functions.php

<?php

// Written but not tested
add_action('save_post', function ($post_id, $post, $update) {
  // Find a reason not to fire
  
  // Serving rest request
  if (!wp_is_serving_rest_request()) {
    return;
  }
  
  // Doing an autosave
  if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) {
    return;
  }

  $is_autosave = wp_is_post_autosave($post_id);
  if ($is_autosave) {
    return;
  }
  
  // If we're here, we're all good
  if($update) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, get_permalink($post_id);
    // Setting request to PURGE
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PURGE");
    curl_exec($ch);
    curl_close($ch);
  }
});

Can add archive URL's if not a page (if used) or a custom post type.