# Order Book Every order instruction will go into the single-threaded order book engine. However, DeltaDeFi's order book is indeed completely detached from the on-chain logic. ### Order Book Engine * Provide instructions on which order is matched or cancelled * Ensuring the fairness of the DEX * Purely off-chain ### On-chain Validators * Safeguard value movement within DeltaDeFi * Instructions are valid only when approved by the users' private key We acknowledge that fairness is important to traders, therefore, we will make the market trading records available to the public. Such that any malicious behaviours can be detected by the community, posing a soft restriction on our team to behave honestly. To learn more about the order book engine, please visit the whitepaper. --- # 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.deltadefi.io/about/learn/architecture/order-book.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.