Amazon Cognito, one of the most annoying parts of building and creating applications, either mobile or web, is dealing with user authentication. Being able to determine who is and who is not allowed to operate specific services or aspects in application is extremely important. However, it can be a tedious and time consuming operation to set up.

In the past, all of that important user information would have been stored in a garden variety user database. This database might've been hosted onsite or even in the cloud. Either way, it was probably a relational database holding tables of usernames with associated permissions.

When working in AWS land, this means the database would either be hosted on RDS, the Relational Database Service, or by running your own database on EC2 instances. The trouble with using either of these methods is it requires a lot of work to get everything set up and maintain the system. We also have the familiar scenario of people working in the corporate environment.

All of their information is already stored in a directory service like Microsoft Active Directory and we don't want them to have to create yet another login and password for our new custom application. We would prefer that they could sign in with their day-to-day corporate username and password. Well, all these pain points can be resolved by using Amazon Cognito, a fairly small service that can do quite a lot of heavy lifting.