Last year Ryanair went back to using a GDS (global distribution system) and struck a deal with Amadeus. Until that time Ryanair had sought to sell its tickets only via its online presence. The Amadeus will enable Ryanair to sell tickets via travel agents and to customers who would otherwise not have bought directly from the company

More about Amadeus:

Today over 70 low fare airlines have chosen Amadeus as their distribution partner and low fare airline bookings via the Amadeus system increased by 21% during 2013. Since its introduction in 2007, Amadeus’ XML link has enabled low fare airlines to benefit from the reach and yield provided by travel agency distribution without the complexity associated with traditional ticketing processes for airlines. Amadeus’ Light Ticketing enhancements were first deployed by a low cost airline in 2013, allowing travel agents to use standard pricing workflows whilst being able to access the airline’s content from the standard neutral availability flow, modify PNRs and finalise the booking process with the creation of ticket numbers – just as they do when booking traditional flag carriers.
— http://www.amadeus.com/web/amadeus/en_1A-corporate/Amadeus-Home/News-and-events/News/2014_9_24_Ryanair-partners-with-Amadeus-for-travel-agency/1319560217161-Page-AMAD_DetailPpal?assetid=1319606953943&assettype=PressRelease_C