Booking / room booking tokens are base 92 strings of supplier data that the API uses throughout the booking process to be able to complete the booking with the supplier.

Basically, information that doesn't fit into the fields available within the booking journey, but iVectorOne needs them to pass information between calls, and ultimately complete bookings.

Always use the latest tokens and you cannot go wrong - you don't really need to overthink this!

E.g. 
- pass the booking / room booking tokens from the search response into the prebook request for the selected hotel
- pass the booking / room booking tokens from the prebook response into the book request for the selected hotel, as they may have changed since search