ReactPHP is a low-level library for event-driven programming in PHP. At its core is an event loop, on top of which it provides low-level utilities.
Elasticsearch is a database that stores, retrieves, and manages document-oriented and semi-structured data.
A blockchain, originally block chain, is a growing list of records, called blocks, that are linked using cryptography.
Stands for "Peer to Peer." In a P2P network, the "peers" are computer systems which are connected to each other via the Internet.