DAS is a Dapp based on Nervos CKB. "Off-chain computation, on-chain verification" is the unique design of Nervos CKB. For any Dapp running on top of CKB, there are both off-chain computation-related programs and on-chain verification-related code.
Keeper is the "off-chain computation" related programs of DAS and anyone can run without permission. It will issue transactions to modify the on-chain state of the CKB based on the on-chain state of the CKB. These transactions need to be validated by the program responsible for "on-chain validation" before they can be packaged on the chain. Therefore, anyone can implement their own Keeper according to DAS smart contracts
In DAS system, the Keeper program is responsible for batch processing user registration requests and recycling expired accounts, etc. Keeper will be rewarded for each registration request and account recycling process. View Reward Details.