deviceKey

When you enable device remembering, Amazon Cognito issues a device key that you can use for device authentication that bypasses multi-factor authentication (MFA). To implement GetTokensFromRefreshToken in a user pool with device remembering, you must capture the device key from the initial authentication request. If your application doesn't provide the key of a registered device, Amazon Cognito issues a new one. You must provide the confirmed device key in this request if device remembering is enabled in your user pool.

For more information about device remembering, see Working with devices.