Flight price tracker Yapta's value proposition sounds a bit like Robin Hood of the travel industry. It will not only track travel prices for you, but to help you get a refund should the price of your reservation fall after you’ve booked it. I wouldn’t be surprised if Yapta can also be used to retrieve kittens from high branches, but that part of the Yapta API isn’t documented yet.
Yapta relies on JSON schema definitions and provides a detailed encyclopedia of its API messages. This gives developers an in-depth look the Yapta API data surface. This API release is in beta, and developers must go through an application process to gain access. So it seems that the current public API documentation is really a bit of a tease. The good news is that during this beta phase Yapta openly invites API users to interface with its developers.
Yapta sounds like a technically robust API since it is taking information from multiple disparate data sources and then offering it up to the API user. A quick look at the site shows that Yapta outsources travel reservation searching to Kayak. Yapta also uses OAuth to protect user credentials. Maybe in a month of two there will be an open source implementation of the Yapta API on github. We can hope. There is sure to be some excitement around this offering since Yapta’s price tracking API is the first of this type openly available in the travel industry.