Southwest Direct Access (SDA) requires a separate agreement with Southwest to be in place before configuration can take place.
...
Does the service support schedule-based search?
Yes, schedule results will be requested through SDA and presented inline with other airlines.
Does the system still use the Global Distribution System (GDS), such as Sabre, to access fares and schedules?
No, all low fare and schedule search results come through SDA.
Is all fare data stored for customers?
Yes, all fare information is stored.
Purchase and HoldĀ
Are travelers allowed to hold trips?
...