Cryptocurrency has been around since 2009 when bitcoin was first open-sourced. As perhaps the most recognizable form of cryptocurrency, bitcoin is both its own currency as well as a decentralized payment system with no central bank controlling it. The system is driven by peer-to-peer transactions which are recorded in a public ledger called the blockchain. Since the system is decentralized, developers are free to create new services and applications, many of which are backed by an API, that utilize both bitcoin and blockchain. Recently the price of bitcoin has surged; CNBC reported that if you bought $100 worth of bitcoin in 2010, it would be worth $73 million today. The price rally got us wondering if there has been a similar surge in developer interest in bitcoin. This article uses our directory data to look at the growth of APIs in this space.