Klaviyo added WhatsApp to channel affinity.

Klaviyo is teaching merchants that channel choice should be optimized from customer behavior, not guessed by a campaign manager. TailoredTexting should answer with reply-aware routing: what the shopper just texted should decide whether the next touch is SMS, WhatsApp, email, push, silence, or a human.

Source: Klaviyo What’s New, Fetched June 18, 2026; Klaviyo says operators can include WhatsApp in Channel Affinity to optimize message delivery across email, SMS, push, and WhatsApp.

What happened: Klaviyo now lets brands include WhatsApp in Channel Affinity, so delivery can be optimized across email, SMS, push, and WhatsApp. That puts WhatsApp beside SMS inside the same customer-data decision layer instead of treating it as a side channel.

Why it matters

This is a control-plane move. Klaviyo wants the merchant to believe the CRM knows the customer’s preferred channel better than any standalone texting tool. Attentive is already selling coordinated pressure across SMS, email, RCS, and push. Postscript is defending SMS as the specialist sales thread. Klaviyo’s move says the winner will decide not only what to send, but where the next message should land.

Tailored implication

Build preferred-channel reply routing. Every inbound SMS should update a customer record with reply urgency, channel confidence, language, buying stage, support risk, and whether the shopper is asking for a conversation or just a link.
When a shopper replies with buying intent, keep the thread in SMS if speed matters. When the reply needs rich context, hand it to WhatsApp or email. When the reply signals fatigue, suppress the next campaign across Klaviyo, Attentive, Postscript, and push.
Expose this as an operator rule table: reply type → best channel → minimum wait → proof asset → escalation owner. The founder needs a routing system, not another campaign opinion.

Bottom line

Klaviyo is expanding channel affinity into WhatsApp. TailoredTexting should make the customer reply the deciding signal for where the next touch belongs.