Polkadot uses NPoS (Nominated Proof-of-Stake) as its mechanism for selecting the validator set. It is designed with the roles of validators and nominators, to maximize chain security. Actors who are interested in maintaining the network can run a validator node. At genesis, Polkadot will have a limited amount of slots available for these validators, but this number will grow over time to over one thousand.

The system encourages DOT holders to participate as nominators. Nominators may back up to 16 validators as trusted validator candidates.

Validators assume the role of producing new blocks in BABE, validating parachain blocks, and guaranteeing finality. Nominators can choose to back select validators with their stake.

The staking system pays out rewards equally to all validators regardless of stake. In other words, having more stake on a validator does not influence the block rewards they receive. However, there is a probabilistic component to reward calculation (discussed below), so rewards may not be exactly equal for all validators in a given era.

Distribution of the rewards are pro-rata to all stakers after the validator payment is deducted. In this way, the network incents the nomination of lower-staked validators to create an equally-staked validator set.

Bill Laboon, W3F Technical education lead, talks about how to pick validators to nominate (stake) on Polkadot.

https://polkadot.js.org/apps/#/staking
https://wiki.polkadot.network/docs/en/learn-staking
https://wiki.polkadot.network/docs/en/maintain-nominator
https://wiki.polkadot.network/docs/en/maintain-guides-how-to-nominate-polkadot

#npos #polkadot #blockchain #nominate #staking