How do we check if a user is logged in

Question

I’m building an application where I need to verify a user's login status across pages. What are the best practices for maintaining a user’s session state and checking if they’re logged in? Should I use cookies, local storage, or session tokens, and how do I handle this securely?

If there’s a straightforward method for validating login status in web applications, I’d love to hear about it.

Answer 1

Here are a few common techniques for determining whether a person is logged in and safely preserving their session between pages:

1. Use JWT (JSON Web Tokens)

• Store the token in a secure, HTTP-only cookie or in memory.
• Check login status by verifying the presence and validity of the token on each request.
• Best practice: Avoid storing tokens in localStorage to protect against XSS attacks. Instead, HTTP-only cookies are more secure.

2. Session Cookies

• Set a session cookie when the user logs in; the server can check this cookie on each request.
• Check if the session exists on each page load by calling an API endpoint like /auth/check-session.
• Best practice: Use the Secure and HttpOnly flags on cookies and enable SameSite to prevent CSRF attacks.

3. Server-side Session Management

• Store session data (like user ID or token) in the server memory or a database.
• Verify session by checking a session ID cookie against the server's session store. If the session ID is valid, the user is logged in.
• Best practice: Use secure session management libraries like express-session (for Node.js) with a database-backed session store for persistence.

4. Check Login Status in Frontend

• On page load, call an endpoint like /auth/status to confirm the user’s login status. If the token or session is valid, proceed; otherwise, redirect them to the login page.
• Best practice: Implement a single point of verification (e.g., middleware) to check the login status server-side for all routes that require authentication.