Usage and Purpose of the Machine Account
A Machine Account is a Flow account which is used autonomously by a node to interact with system smart contracts. Machine Accounts contain Cadence resources granted to network participants which are used to participate in smart-contract-mediated protocols. Currently, Machine Accounts are used in the Epoch Preparation Protocol, which prepares the network for the next epoch.
Your Machine Account is distinct from the account you use for staking your node (your Staking Account). The Machine Account is intended for use by node software and does not have access to your staked tokens or staking rewards.
Currently Machine Accounts are required only for
For new node operators, Machine Accounts are created during the staking process in Flow Port. For node operators who initially staked prior to the introduction of Machine Accounts, Machine Accounts can be created for your staked nodes by following this guide.
Machine Accounts must maintain a balance of liquid FLOW tokens to pay fees on transactions they submit to system smart contracts. Typically very few transactions will be sent (about 1-5 per week) however more may be required under certain circumstances and network conditions.
Because some transactions sent by the Machine Account are system critical, we recommend maintaining a balance sufficient to accomodate worst-case transaction submission numbers at all times.
We recommend a minimum balance of 0.001 FLOW for collection nodes and 0.1 FLOW for consensus nodes, but more is definitely safer if you plan on operating your node for a very long time.
A node operator can easily withdraw their FLOW from their machine account if they decide they don't need them there any more.