# Planning your Amazon Cognito design
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The choices in this chapter are easier to make up front than to change later. This chapter covers:
+ **Choosing an authentication approach**—how your users sign in.
+ **Common scenarios**—architecture patterns to match against your application.
+ **Multi-tenancy**—if you serve more than one customer organization, strategies to isolate each tenant's users and data are covered in [Building B2B multi-tenant applications](multi-tenant-application-best-practices.md).