juniorPHP
What are sessions and cookies in PHP?
Updated May 24, 2026
Short answer
Sessions store server-side user data, while cookies store small client-side data.
Deep explanation
Sessions use unique IDs stored in cookies to identify users across requests. Cookies persist data in the browser and can include expiration times. Sessions are generally more secure.
Real-world example
Shopping carts often rely on sessions to maintain state.
Common mistakes
- Storing sensitive data directly inside cookies.
Follow-up questions
- How are sessions identified?
- Can cookies be disabled?