Hi @WWVintners, 

Thanks for sharing your question with us! Can definitely understand wanting to to age-gate your messages to prevent anyone underage from receiving your messages, especially because SMS messages are more heavily filtrated for compliance. 

I would definitely recommend, using a third-party service to age-gate, not only who receives your SMS messages, but also your website, like Juno. However, to age-gate your SMS, you could create a mult-step signup form to collect users’ phone numbers. The first step of the form can ask the user if they are 21+ with an email/sms field before they proceed any further. You can add a hidden profile property  to the "yes", to add a property to the user’s profile that will attach with the value  "over 21 = yes". The ‘No’ button can essentially close out of the form and/or apply a hidden input of "over 21 = no".

I’d still suggest looking into the third-party age-gate application mentioned before, and of course reaching out to your legal team or lawyers as Klaviyo cannot give official legal council. 

Thank you for your participation in the Community! 

-Taylor 

Hi again @WWVintners, 

Upon conversing more with my colleagues, I can confirm that you will need to use a third-party application to age-gate your website and the Klaviyo multi-step form will not be a suitable process to age-gate your SMS! 

-Taylor 

Hi Taylor,

Thank you for the update. I will go ahead and reach out to Justuno. :)