AWS Amplify Cognito Pricing: What is a sync operation

1. Amazon Cognito Sync Operation is an AWS service and client library that enable cross-device syncing of application-related user data. You can use it to synchronize user profile data across mobile devices and web applications. The client libraries cache data locally so your app can read and write data regardless of device connectivity status.

2. No. Attributes are pieces of information that help you identify individual users, such as name, email address, and phone number. A new user pool has a set of default standard attributes. You can also add custom attributes to your user pool definition in the AWS Management Console.

Don't store all information about your users in attributes. For example, keep user data that changes frequently, such as usage statistics or game scores, in a separate data store, such as Amazon Cognito Sync or Amazon DynamoDB. https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-settings-attributes.html