# UsernameConfigurationProperty

Case sensitivity of the username input for the selected sign-in option.

When case sensitivity is set to `False` (case insensitive), users can sign in with any combination of capital and lowercase letters. For example, `username` , `USERNAME` , or `UserName` , or for email, `email@example.com` or `EMaiL@eXamplE.Com` . For most use cases, set case sensitivity to `False` (case insensitive) as a best practice. When usernames and email addresses are case insensitive, Amazon Cognito treats any variation in case as the same user, and prevents a case variation from being assigned to the same attribute for a different user.

- Source: Generated code
- Type last changed: v2.93.0 · 23 Aug 2023

## Example

```ts
// The code below shows an example of how to instantiate this type.
// The values are placeholders you should change.
import { aws_cognito as cognito } from 'aws-cdk-lib';
const usernameConfigurationProperty: cognito.CfnUserPool.UsernameConfigurationProperty = {
  caseSensitive: false,
};
```

## Properties

- `caseSensitive`: boolean | [IResolvable](/cdk/api/v2/docs/aws-cdk-lib.IResolvable.html) — Specifies whether user name case sensitivity will be applied for all users in the user pool through Amazon Cognito APIs.

  For most use cases, set case sensitivity to `False` (case insensitive) as a best practice. When usernames and email addresses are case insensitive, users can sign in as the same user when they enter a different capitalization of their user name.

  Valid values include:

  - **true** - Enables case sensitivity for all username input. When this option is set to `true` , users must sign in using the exact capitalization of their given username, such as “UserName”. This is the default value.
  - **false** - Enables case insensitivity for all username input. For example, when this option is set to `false` , users can sign in using `username` , `USERNAME` , or `UserName` . This option also enables both `preferred_username` and `email` alias to be case insensitive, in addition to the `username` attribute.