Moonbeam's inflation rate is planned at 5% per annum.
The minimum amount required to delegate on Moonbeam is 5 MOVR. However, it is always advised to leave at least 1 MOVR in your account to cover any future transaction fees, such as unstaking.
There is currently no slashing on Moonriver or Moonbeam. If a collator does not perform as expected, they will simply not receive rewards.
The Moonriver team is working on a staking dashboard that will allow nominators to view collator performance. If a collator fails to produce blocks, nominators will be able to see that poor performance and can stop nominating their stake to poorly performing collators.
The service fee on Moonriver is set by the protocol, and not by Coinbase Cloud. This is a 20% service fee on all rewards earned by tokens delegated to any Moonriver validator. The service fee is paid to Coinbase Cloud automatically by the protocol.
Updated 9 months ago