OAuth
Open Authorization
ELI5 — The Vibe Check
OAuth is the system behind 'Login with Google.' Instead of making a new account, you let Google vouch for you. Google checks your identity and tells the app 'yep, this is really who they say they are' without ever giving the app your Google password.
Real Talk
OAuth is an open standard for delegated authorization that allows applications to access user resources on other services without obtaining passwords. The user grants permissions to a third-party app via an identity provider. OAuth provides access tokens, not authentication by itself.
When You'll Hear This
"Implement OAuth so users can log in with GitHub." / "OAuth handles the authorization — OpenID Connect handles the identity."
Related Terms
API Key
An API key is your password to use an AI service. You include it in every request to prove you're allowed to use the API and so they know who to charge.
Authentication (AuthN)
Authentication is proving you are who you say you are.
Authorization (AuthZ)
Authorization is deciding what you're allowed to do after you've proven who 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.
OAuth2
OAuth2 is the updated version of OAuth that everyone actually uses today.
Token
In AI-land, a token is a chunk of text — roughly 3/4 of a word.