Yes, you can use a unique ID. You would continue to use the same field named email but rather than set that value to be an email address you would instead pass us a unique ID as the email value.
Example from Javascipt SDK:
window.wootricSettings = {
email:'nps@example.com',// TODO: Required to uniquely identify a user. Email is recommended but this can be any unique identifier.
created_at: 1234567890,
account_token: 'NPS-xxxxxxx'
};
That ID will show up in place of the email address in your dashboard under the feedback tab to identify each response.
This approach can be used for in-app web and mobile surveys, survey links, and email templates.
Intercom messenger app surveys require an email address, as do email surveys sent by Wootric.