What is Hashgraph : Hashgraph is an alternative to blockchain — a first generation tech with severe constraints in terms of speed, fairness, cost, and security.
Technology : Hashgraph aims to provide the benefits of blockchain as a distributed ledger technology without the limitations. When the new messages include the hash of previous messages into one, then you have the entire history of who talked to who in the network and in what order.
Hedera, a cryptocurrency startup has decided to launch a new virtual currency platform named Hedera Hashgraph Platform in the second half of 2018.
Swirlds and Hedera: https://www.hederahashgraph.com/