UUID versions are not interchangeable. The right choice depends on whether you need random identifiers, time ordering, compatibility with an existing system, or a stable namespace-based value.
UUID v4 for general random IDs
UUID v4 is random and widely supported. It is a practical default when you need a unique identifier but do not want the identifier to expose ordering information.
UUID v7 for sortable identifiers
UUID v7 includes a timestamp component and is designed to sort by creation time while retaining a large random component. It can be useful for database keys and event identifiers when chronological locality matters.
Use v1 and namespace versions intentionally
UUID v1 contains time and node-related information, so consider its information exposure before using it. Namespace-based versions are useful when the same input must consistently produce the same identifier.