# Order Book VDEX operates a central limit order book with bids and asks sorted by price. Orders can be placed in integer multiples of the [asset tick size](/trading/vdexcore/contract-specifications.md). Orders are matched in price-time priority. The clearing house verifies margin during order creation and matching. If margin is insufficient to cover the full order, it will be reduced until a partial match can be executed. VDEX orders execute peer-to-peer via [Virtual Rollups](broken://pages/o3FwAB5qpfDXyxpSLdU2), not through a centralized backend or blockchain. Transactions are not batched and are executed in the order received. This prevents MEV attack vectors whereby orders are placed and processed jointly. --- # 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.vdex.trade/trading/vdexcore/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.