# Keeper DAS is a Dapp based on [Nervos CKB](https://nervos.org). "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](https://github.com/DeAccountSystems/das-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](/docs/contribute-to-das/build-together.md). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.da.systems/docs/contribute-to-das/keeper.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.