Stellar is an open-source network with the mission to "create equitable access to the global financial system". Stellar is maintained by the Stellar Development Foundation, a non-profit organization established in 2014.
Its goal is to build a global financial infrastructure that makes it easy to move traditional forms of money and access new markets. This goal is realised by faciliating transactions of digital representations of currencies (such as USD, EUR, BTC, etc) on a single ledger.
Stellar uses the Stellar Consensus Protocol for achieving network consensus, which is based on Federated Byzantine Agreement. Stellar provides various Software Development Kits and APIs to make building on and using Stellar as accessible as possible.
Stellar's token, the Lumen (XLM), is used for staking and constitutes the payment method for all services the system provides.