Importing and updating contacts
with 
To automate the import and update of contacts from one application to another.
Emails, SMS and voice messages
with
To automate the sending of messages between Digitaleo and your application.
What you can do with 
Synchronise your contacts on one side only
Example: create a contact in Digitaleo when a customer makes a purchase on Shopify.
Automate your SMS, emails and voice messages
For example: send an email to a customer with Digitaleo when their order is updated in Shopify.