Session
Your app remembering you're logged in between page loads.
What is Session?
A session tracks that you're logged in. Without sessions, you'd have to log in on every page. Sessions can be stored in cookies or JWTs. When you "clear your cookies," you end all your active sessions.
Sessions have a lifespan. Most expire after 30 days or when you explicitly log out. This is a security feature — if someone steals your session, it eventually expires.
In Vibe Coding
Supabase and Clerk handle sessions automatically. When you use their SDKs, your app just checks "is there an active session?" to know if someone is logged in. You don't manage sessions manually.
Example
For example: You're logged into Netflix. You browse different pages, add shows to your list, watch a movie — the session keeps you logged in the whole time without asking for your password again.