The next phase step is to set up callbacks so that you are notified when a booking is fulfilled or fails. Callbacks need to be set up only once, regardless of how many different Gordian services you end up integrating in your journey flow.
To facilitate callbacks, you'll need to configure your IP whitelist to allow calls from Gordian's services.
Please allow the following IP addresses:
Create Callback Subscription
After whitelisting the IPs, you can create a callback subscription