The below request will return a list of service codes that are available on your Shiptheory account, to use with your API shipment bookings
$ch = curl_init('https://helm.shiptheory.com/api/services');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
'Authorization: bearer yourbearer',
$result = curl_exec($ch);
Enter your bearer token in the authorization header and you'll get a big list of all the service codes on your account which you can use when booking in a shipment via the API.