Just trying to get the best method for testing adding/updating contacts via a cronjob without interfering with the current contacts list. Will I need to create a new account specifically for testing?
Twilio SendGrid developer evangelist here.
If you want to make requests to the API as part of your testing (which I normally advise against, as testing 3rd party services should be unnecessary), and you don't want to affect your data, then you don't need a completely new account, but you can use a Subuser account.