The possibility to send email invitations via the 1KA system also allows you to track respondents, so you can check who on the list has responded and who has not, which is the basis for sending reminders. The use of the 1KA system for sending e-mail invitations is only possible in combination with your own SMTP server settings.
Tracking respondents is not possible if you have the same URL for all respondents (i.e. the survey is truly anonymous). In this case it is not possible to identify who has and has not responded to the survey. However, all experience shows that the problems associated with this are significantly less than the benefits of such anonymity.