For long distance travel, especially on-rail, there is increasing used of yield managed fares with dynamic pricing, provided by web services. Note that such applications increase rather than decrease the need for standards such as NeTEx as such applications nonetheless require a machine readable definition of the access rights fare structure and usage conditions that apply to the products for which prices are supplied. Furthermore the search parameters used to find the best fare for a user (such as age, possession of rail cards, fulfilment method etc) need to correspond to the properties of the fare product. The NeTEx Part3 specification and UML model includes an annex showing a sample fare query which shows all the NeTEx model elements relevant for constructing a Fare API.