Cartid

Cartid, or cart ID, is the identifier that represents a shopping cart within an e-commerce system. It serves as a pointer to the cart’s data in the backend, allowing items added by a user to be retrieved, displayed, and updated across pages and sessions.

Generation and storage

Cart IDs are typically generated by the server when a cart is created, using random tokens, UUIDs, or database keys. The ID is transmitted to the client and stored in a cookie, a URL query parameter, or in local storage. Requests to add or remove items include the cart ID to indicate which cart to modify. The ID may be treated as a session-level token or a persistent cart reference, depending on the platform’s design.

Lifecycle and persistence

A cart ID may be associated with a guest cart that persists for a defined period or until checkout, or it may be linked to a user account so the cart endures across devices. If a user logs in, many systems merge the guest cart with the user’s saved cart. Cart IDs can expire after inactivity or be invalidated after checkout or cart abandonment according to site policy.

Security considerations

Cart IDs should be protected to prevent exposure. Practices include using HttpOnly and Secure cookies, encrypting or hashing tokens, employing short expiry, and avoiding predictable ID generation to reduce risks such as cart fixation or leakage through URLs or referer headers.

Interoperability

Different platforms may refer to cart IDs as cart_token or cart_key. In APIs, the cart resource is typically addressed by this identifier, tying together item data, quantities, and pricing for the checkout flow.