A method of revenue management of an inventory of items in order to optimize the availability of one or several item(s) requested by a user, method comprising the steps of calculating an online estimate of a first element associated with the request; calculating an online estimate of a second element associated with the request; comparing the estimate of the first and second element to determine whether or not requested items can be granted to the requestor. The optimized calculations take place in real time and are handled by a single on-line system that does not need to rely on uploads of recommendations from an external off-line optimization system.