Auth Basics

Learn the fundamentals of auth basics in FastAPI.

🎯 Core Concept

Authentication verifies user identity through credentials. Authorization controls what authenticated users can do. Together they protect API endpoints from unauthorized access.

📖 What You'll Learn

In this section, you'll understand:

• Multiple authentication methods (API keys, JWT, OAuth2)

• Token-based authentication and refresh patterns

• Role-based access control (RBAC)

• Securing endpoints with dependencies

• Real-world authentication flows

💡 Simple Authentication Example

from fastapi import FastAPI, Depends, HTTPException
from fastapi.security import HTTPBearer, HTTPAuthenticationCredentials

app = FastAPI()
security = HTTPBearer()

async def verify_token(credentials: HTTPAuthenticationCredentials = Depends(security)):
    if credentials.credentials != "valid-token":
        raise HTTPException(status_code=401, detail="Invalid token")
    return credentials.credentials

@app.get("/protected")
async def protected(token: str = Depends(verify_token)):
    return {"message": "You are authenticated"}

🔍 Key Authentication Methods

• **API Keys**: Static tokens in headers (simple, suitable for server-to-server)

• **Basic Auth**: Username/password in Authorization header (requires HTTPS)

• **JWT Tokens**: Self-contained tokens with claims (stateless, scalable)

• **OAuth2**: Industry-standard authorization with scopes (third-party integrations)

🔑 Key Takeaways

• ✅ Understand the purpose of auth basics

• ✅ Know when to apply this pattern

• ✅ Recognize its benefits in real-world scenarios

• ✅ Be prepared to use it in your projects

Ready to explore more? Check out the advanced section for production patterns and edge cases.