The MultiChain API boasts "feeling at home" if you’re familiar with bitcoin.
The API has maximal compatibility with Bitcoin Core, the reference client for the bitcoin network.
As a fork of Bitcoin Core, MultiChain shares the following technical characteristics: Command-line arguments, Network protocol, JSON-RPC API, Transaction format, Script language, and Block format.
The robust documentation offers basics of working with MultiChain such as: "How to create or connect to a blockchain", "Customizing your blockchain parameters and API commands for controlling MultiChain", as well as information about compatibility with Bitcoin Core.
Eighteen APIs have been added to the ProgrammableWeb directory in categories including Music, Email, TV, and Bitcoin. Highlights include an API for creating Datomic databases and connecting data to them, and an API for MultiChain blockchains. Here's a rundown of the latest additions.