In Practical Usage, Inventory/Content Owners/Consolidators, offers Inventory/Content over an interface (Can be An API, XML Interface over JSON etc) which can be utilized by the Business using the application to fulfill product selling and instant confirmation at both ends.

And this is what we specialize in doing, integrating the content (irrespective of the content type i.e. Flights, Hotels, Card etc), available from any third party source (irrespective of the format of availability) seamlessly to the application (Irrespective of the language or Technology used).