Keeper
An automated bot that performs a protocol's upkeep — executing liquidations, harvests and rebalances — for a reward.
A keeper is an incentivized bot that performs time-sensitive maintenance tasks a protocol can’t trigger by itself, since smart contracts don’t run on their own schedule. Keepers monitor conditions and, when one is met, submit the transaction — liquidating an unhealthy loan, harvesting a vault’s rewards, updating an oracle — collecting a fee or penalty share for the service.
Keepers are the invisible robotic workforce keeping DeFi solvent and current. Their competitiveness matters: reliable, well-incentivized keepers execute liquidations promptly, preventing bad debt; sluggish or under-incentivized keeper networks are a hidden risk during fast crashes when everything needs liquidating at once.