When I sign up through Google, it says Apptoto will be able to "manage your calendars" and "Manage your contacts", this makes me nervous.

Don’t worry! We won’t make any changes to your calendars or contacts unless you ask us to through the process of using Apptoto. We mainly ask for those permissions so that we can read from your calendars and contacts to provide the messaging service as advertised.

Feel free to call us or send an email to support@apptoto.com if you have any questions.