Authentication
How an app checks who you are, usually by having you sign in.
What it is
Authentication answers "who is this?" It's the sign-in step: a password, a code sent to your email or phone, a "Continue with Google" button, or a magic link.
Once someone is authenticated, the app remembers them for a while (a session) so they don't sign in on every page.
Authentication is not the same as authorization. Authentication proves who you are; authorization decides what you're allowed to do. Asking for "login" usually means you need both.
How to ask for it
“Add a login so people have their own stuff.”
“Add authentication with email verification codes (no passwords). After signing in, each user only sees their own projects. Signed-out visitors see the landing page; every other page requires sign-in.”
"Add a login" leaves the method and what's protected open; the prompt picks the sign-in method and says which pages need it.
You've seen this in
- TSigning in to Gmail
- N"Continue with Google" on Notion
- FFace ID unlocking your banking app