These Pythom bindings for Bittrex can interface the Bittrex API with an existing python program. The library is open source, however, the Bittrex API requires an API key for use. The library is not officially owned by Bittrex, though it's usage is endorsed by Bittrex on their API documentation page.
BIPS, Bitcoin payment system, allows users to buy or sell online using Bitcoin digital currency. In addition to Bitcoin transaction-based apps and an e-wallet, BIPS provides an API that users can integrate with existing workflows and tools. Merchants can utilize Bitcoin currency alongside traditional currency transactions.
Affectiva's emotional measurement API has been around for a couple of years now. Affectiva has seen adoption by marketers, publishers, gaming companies, and chat services. However, Affectiva believes it can greatly expand the use case scenarios by offering its service at no charge to startups.