# Historical Data Engine **Types of Data Available** * **Historical Market Data**: Includes historical prices, trading volumes, and liquidity metrics. * **Protocol Performance Data**: Tracks historical performance metrics of different protocols, such as interest rates and collateral ratios. * **User Activity Data**: Records user interactions with protocols over time, such as borrowing, repaying, and liquidation events. #### **Window Size** * The Historical Data Engine supports various window sizes, allowing users to query data over different time periods, ranging from minutes to years. #### **How to Access** * **APIs and GraphQL endpoint**: The Real-Time Data Engine provides RESTful APIs and GraphQL endpoint that developers can use to access various data points. Detailed documentation and usage examples will be made available soon in Developer portal. --- # 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.lucidity.finance/protocol/data-engine/historical-data-engine.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.