Hey ​@Nico01,

As of now, there are 4 ways to pass WhatsApp consent into Klaviyo. Via a Klaviyo form, a Keyword (like an SMS subscribe keyword), API, or a WhatsApp subscribe link or QR code. There isn’t currently a way to collect WhatsApp consent at Shopify checkout, at least not through the Shopify integration. That being said, you could use the Bulk Subscribe Profiles endpoint to make an API call from Shopify that could accomplish this, with a bit of custom coding.

For new customers, I’d recommend sticking to a Klaviyo form, or having a keyword/QR code posted somewhere on your site or social media that gets a fair amount of traffic.

While we do plan to add transactional consent collection to our forms in the near future, the best way to collect transactional consent is via API (or list upload, but that’s obviously a more manual process). This article here speaks all about WhatsApp consent, and the section I linked contains an example Bulk Subscribe Profiles payload that includes both marketing and transactional WhatsApp consent. You can base your API calls on this payload.

To address your original question, since WhatsApp is such a new channel, I can’t confidently tell you the “best” way to collect consent from your existing subscribers, but you certainly can create a wa.me link and add it to buttons/links in your emails. That being said, if any other marketer wants to weigh in on this thread and let us know how you’ve been collecting WhatsApp consent from your subscribers, we’d love to hear your tips!