Validator Nodes (also known as Validators):
These nodes validate the transactions in the network by participating in the consensus. They will have to stake SHM to be able to participate. Shardeum will reward honest validators with SHM for participating in transaction validation and consensus. Validator nodes don’t store the whole history and in fact they only store the state of accounts they handle, so they will be lightweight.
Archive Nodes:
Archive nodes maintain the entire Transaction history. Archive nodes may or may not have to stake SHM (WIP), but they will earn a portion of the network reward (WIP) as an incentive to store historical data.
Standby Nodes:
These are validator nodes standing by in the network and not currently participating in consensus. Standby nodes help scale the Shardeum network quicker when more transactions are pending. At the end of every cycle, the oldest active validators in the network are rotated out for standby validators for optimum security.