isSignedIn

isSignedIn is a common naming convention used in software development to indicate whether a user or entity is currently authenticated within a system session. It is typically a boolean value that reflects the presence and validity of authentication credentials, such as a session cookie, token, or signed-in user object.

In client applications, isSignedIn is often exposed as a property or derived from the authentication state store. It is used to control user interface elements (for example, showing a sign-out option or hiding restricted features) and to decide whether to initiate a sign-in flow. In server contexts, the concept may be represented by session state or validation of an access token for protected resources.

Because authentication state can change (tokens expire, sessions end, users sign out from other devices), isSignedIn is commonly treated as asynchronous or reactive. Initial checks may render a loading state until the system confirms the status, and the value can be refreshed after token renewal.

Security considerations: isSignedIn should not be trusted for authorization on the client side by client code alone; server-side checks are required to enforce access control. Use short-lived credentials with secure storage, and implement proper sign-out and revocation processes.

Origins of the term vary by framework; isSignedIn may be implemented as a boolean flag, a computed property, or a function. It is part of broader authentication and session management concepts, alongside similar terms such as isAuthenticated, isAuthorized, and isLoggedIn.