All dataclips are secured through an unguessable URL. Heroku also allows only selected users to view your dataclip; this is done by adding the user e-mail in the dataclip's configuration. This functionality is only available on the Standard tier, Premium tier, or Enterprise tier plan.

In order to set the display only for selected users, you must click on the Settings link. Then, in the Security Permissions section, choose the Only to authorized users option. After that, add the e-mails that you want to allow, and finally, click on the Save Permissions button:

Dataclip available only to authorized users

When someone accesses the URL of your dataclip, they will be informed that the dataclip is protected and that the user is required to log in to view the results:

The user must log in to view the results of the dataclip