Ripple is a centralized blockchain protocol/ledger designed with a specific use case in mind: allowing banks to settle global cross/interbank transactions cheaply, efficiently and securely via the blockchain.
The Ripple ledger was conceptualized and developed in 2012-2013 by software developers Ryan Fugger and Jed MacCaleb. They founded RippleLabs, a San Diego-based legal entity that controls and operates most of the 100+ nodes of the RippleNet blockchain.
It is important to distinguish a number of names and terms as well as entities around the Ripple project:
Ripple (XRP) is the name of the utility token in the network; it is used as a bridge currency between global banks who settle fiat payments between each other.
RippleNet is a decentralized global network of banks and payment providers using Ripple’s distributed financial technology
Ripple Labs Inc. is the San Francisco-based company behind the development and operation of RippleNet.