# Cart Service Provides a high-performance, extensible cart that holds products for later checkout. ### Key features and benefits * Supports authenticated user carts * Merges carts seamlessly * Provides a single cart across sites or an individual cart per site * Makes the cart persistent for later checkout * Allows adding, removing, modifying, and deleting cart entries * Supports products with unknown weight at checkout * Calculates prices with high precision, up to 16 digits (ranging from 1 quadrillion (1,000,000,000,000,000) to 0.000000000000001, scale of 15) * Supports multi-currency with appropriate format (no fractions, ISO standard defined fractions, or custom fractions) * Supports promotions and discounts * Supports coupons * Handles deposits and fees * Supports net and gross prices * Offers high-performance, auto-scaling capabilities * Handles external prices and fees * Provides a ready-to-use cart implementation * Guarantees response times and high availability * Supports web, native/reactive mobile, gaming consoles, and other IoT devices --- # 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://developer.emporix.io/api-references/api-guides/checkout/cart.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.