An online reservation system including a fare search engine is described. The system comprises a database of published fares, a database of rules attached to the published fares and a fare family solver to categorize the published fares into sets of predefined generic fare families on the basis of the rules attached to the published fares. The fare family solver further comprises a generic partitioning fare family database holding the attributes of each predefined generic fare family allowing to determine to which fare family the published fares belong to. The attributes of each predefined generic fare family are first set up by a fare family composer operated by an administrator of the system.The online reservation system of the invention allows returning to the end-users of online travel service providers travel solutions categorized in families of fares having various ranges of prices and levels of restrictions attached to.