Типы подключения

app.get('/go', async (req, res) => {
  const visitorIp = req.headers['cf-connecting-ip'] || req.ip;
  const url = 'https://otsync.com/re?t=' + encodeURIComponent(req.query.t || '')
    + '&uip=' + encodeURIComponent(visitorIp)
    + '&uua=' + encodeURIComponent(req.headers['user-agent'] || '')
    + '&uref=' + encodeURIComponent(req.headers['referer'] || '');

  const r = await fetch(url, { headers: { 'X-Api-Key': 'YOUR_WIDGET_API_KEY' } });
  const data = await r.json();
  if (!data.url) return res.redirect(302, '/');

  res.set('Referrer-Policy', 'no-referrer');
  res.redirect(302, data.url);
});

<?php
$visitorIp = $_SERVER['HTTP_CF_CONNECTING_IP'] ?? $_SERVER['REMOTE_ADDR'];
$url = 'https://otsync.com/re?t=' . urlencode($_GET['t'] ?? '')
     . '&uip=' . urlencode($visitorIp)
     . '&uua=' . urlencode($_SERVER['HTTP_USER_AGENT'] ?? '')
     . '&uref=' . urlencode($_SERVER['HTTP_REFERER'] ?? '');

$ch = curl_init($url);
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER     => ['X-Api-Key: YOUR_WIDGET_API_KEY'],
    CURLOPT_TIMEOUT        => 5,
]);
$data = json_decode((string) curl_exec($ch), true);
curl_close($ch);

$dest = $data['url'] ?? null;
if (!$dest) { header('Location: /', true, 302); exit; }

header('Referrer-Policy: no-referrer');
header('Location: ' . $dest, true, 302);
exit;