🔐 Authentication Basics (JWT) & FastAPI Security

Authentication is not just a login page. 🙅‍♀️

It is about understanding how a backend identifies a user, verifies their identity, issues a token, and protects private API endpoints .

In this guide we'll learn everything from absolute zero:

✅ How JWT works internally

✅ What OAuth2PasswordBearer actually does

✅ Why password hashing is necessary

✅ How Depends() makes authentication reusable

✅ How all these pieces connect in a real React + FastAPI + PostgreSQL project (my Social Feed app)

Simple examples, real-world analogies, Python code and execution flows. No assumed knowledge. Let's go!…