These days, most client applications require Authentication, authorization and user management. In this article, I explain how you can quickly build a client app with full-fledged, fully scalable authentication, authorization and user management using aws cognito. For the demo purpose, I use an isolated secure aws S3 space for every user where users can store personal images. No one else other than the logged in user can access the images stored. Demo app is built using ionic4(angular6).