Which OTA's display "Fare Class"
 

One of the things that frustrate me the most when booking online is the increasing trend of Online Travel Agencies to NOT show the "Fare Class" or "Fare Rules" upon initial search. This is followed by OTA's that continue to NOT show the Fare Class or rules after entering personal details and then finally NOT showing any rules whatsoever once the ticket is purchased. Even more frustrating is when in some cases the only way to know what rules are in effect is to contact the agency after the fact only to be told the most restrictive rules apply. Even worse is when you must pay for this customer service.

The only way I know to be informed is to be able to see the fare class or fare rule on initial search. It is for this reason I search Expedia as this is one of the few sites that divulge such details in advance.

What other online travel agencies are transparent in divulging the Fare Class in advance?

Why use an OTA at all instead of booking direct?

Travelocity and Orbitz show booking classes as well as fare rule summaries.

fareboom shows booking class and fare basis. I have never booked anything through this OTA though.

Also, faredepot shows fare basis whose first character is normally the booking class.

Are you referring to fare basis with a ticket designator or something else? (Just trying to figure out what private fares you mean look like on the website).

Certain (more complicated) tickets cannot be booked directly at the airline site, e.g. a multi-stop journeys.
Some airline sites are just awful.