Python JWT Authentication

Implement JWT authentication in Python using PyJWT with HS256 signing, token verification, expiry validation, and FastAPI dependency injection for protected.

Python Auth Jwt Updated: 2026-01-15

Code

snippet

import jwt
from datetime import datetime, timedelta, timezone

SECRET = 'your-secret-key'

def create_token(user_id: str) -> str:
    payload = {
        'sub': user_id,
        'exp': datetime.now(timezone.utc) + timedelta(hours=1),
        'iat': datetime.now(timezone.utc),
    }
    return jwt.encode(payload, SECRET, algorithm='HS256')

def verify_token(token: str) -> dict:
    try:
        return jwt.decode(token, SECRET, algorithms=['HS256'])
    except jwt.ExpiredSignatureError:
        raise ValueError('Token expired')
    except jwt.InvalidTokenError:
        raise ValueError('Invalid token')