[Dracophoenix]

Then how do discount sites like Kayak, Expedia, or Matrix ITA/ Google Flights work without a hitch? The ticket prices are no lower than what SABRE will offer and it doesn't seem like AA is losing money in those cases.

[windowsworkstoo]

There are API’s, just not public ones - only available under commercial agreement

[cratermoon]

SABRE charges per call. That's probably why AA is trying to stamp out this app – it costs them money because it triggers calls through to SABRE.