Useid

Useid is a term commonly used in computing to denote the user identifier, a value that uniquely identifies a user within a system. It serves as a key for associating actions, preferences, and permissions with the correct individual, and it underpins authentication, authorization, and auditing processes.

In practice, a used identifier can take various forms. It may be a numeric ID, a string, or a universally unique identifier (UUID/GUID). Some databases and applications store the value in a field named user_id or uid, while others may adopt a shorter alias such as "useid." The exact format is determined by the system’s design, performance considerations, and the need for cross-system compatibility or privacy constraints.

The primary functions of a used identifier include enabling user-specific access control, linking user-related data across tables or services, and providing an auditable trail of actions. Because IDs are often exposed in logs, URLs, or APIs, many systems treat them as opaque tokens and separate them from sensitive attributes. This helps reduce the risk of user information leakage and supports better privacy practices.

Security and design considerations for used identifiers include ensuring global uniqueness within the relevant scope, protecting against predictable ID enumeration, and choosing storage and indexing strategies that scale with the user base. When integrating across systems, care must be taken to map identities securely and to avoid leaking internal IDs to external observers.

See also: user ID, UID, UUID, GUID, authentication, authorization, identity management.