Smart contracts interact with the outside world through oracles and Oraclize is a provider. They have published code for sample apps on their Github. For example, here is the Kraken Cryptocurrency Price Tracker sample app
He tested with chainlink, which is also an Oracle. I believe it´s more developed, as it has already launched a testnet and is now around40 rank on CMC.
But i believe it´s still soon for this kind of use...