401
ELI5 — The Vibe Check
401 Unauthorized means 'who are you? Log in first.' You haven't proven your identity. It's like trying to enter a club without an ID — they're not saying you're not allowed, they're saying they don't know who you are yet.
Real Talk
HTTP 401 Unauthorized indicates the request lacks valid authentication credentials. Despite the name 'Unauthorized', it specifically means unauthenticated. The server expects credentials (like a JWT or session cookie) to be provided.
When You'll Hear This
"The protected route returns 401 if there's no token." / "401 means not logged in; 403 means logged in but not allowed."
Related Terms
403
403 Forbidden means 'I know who you are, but you're not allowed in here.' You're authenticated but not authorized.
Authentication (AuthN)
Authentication is proving you are who you say you are.
JWT (JSON Web Token)
A JWT is a special kind of token that contains information inside it. It has three parts: a header, a payload (with your user ID, role, etc.
Status Code
An HTTP status code is the server's one-line verdict on your request. 200 means 'perfect, here's what you asked for.' 404 means 'can't find it.
Token
In AI-land, a token is a chunk of text — roughly 3/4 of a word.