Booking Token Unit (BTU) protocol is a standardized building block for any decentralized application (dApp) or web site willing to implement booking features for their end-users. The BTU protocol also brings interoperability among decentralized applications that incorporate it. BTU token will be an ERC20 token running the protocol. All platforms implementing the BTU protocol would benefit from a hybrid approach combining an on-chain smart contract and off-chain software components, providing more scalability.