Quick definition · 2 min Coding term
Authentication
Authentication (or “auth”) is the system that checks who a user is when they log in, so the right person sees the right things.
Think of it like
The bouncer at the door who checks your ID before letting you into your own account.
Example
“Add login” or “add auth” sounds simple but is a common wall. It is also separate from an API key, which is your app’s key, not a user’s.
Why it matters
Almost every real app needs it, and it trips up beginners who confuse it with API keys or general security.
Where you’ll see it
ClerkAuth0Supabase