Cognito

Authentication (who you are) vs authorization to AWS resources (what you can call) - the two Cognito services under one brand name.

Create a user pool and sign up your first user via SDK - five basic and two intermediate examples in Python and TypeScript.

Managing the full user lifecycle - sign-up, confirmation, sign-in, and TOTP multi-factor auth - via the Cognito User Pools SDK.

Pre/post-auth Lambda hooks and a fully custom (e.g. passwordless OTP) authentication flow via the Cognito User Pools SDK.

Token expiry, MFA defaults, secure client-side token handling, and identity pool role scoping - a working checklist for Cognito via SDK.