Harmony Currently Supports three networks
Mainnet is Harmony's production environment. It is running it is running with four shards and 250 nodes per shard.
We are launching Pangaea — an experimental game for thousands of people to interact with the Harmony network, test the limitations of our technology and have lots of fun while earning rewards. Pangaea is created purely for experimental purposes. It will have its own currency for playing and bookkeeping.
Testnet is a testing environment for dApp developers and partners. It is running the latest unstable version of the node software release, but not the nightly build. We do rolling update of the testnet a few times a week. There is not 100% guarantee that transaction on testnet will be persisted across the updates. The testnet is running with two shards and 150 nodes per shard.