Attentive vs Klaviyo (2026): Which Is Better for Ecommerce SMS Marketing?

Overview

SMS has the highest open rates of any marketing channel — 98% open rates versus 20-35% for email. For ecommerce brands investing in retention marketing, SMS is a high-priority channel. The question is which SMS platform to build on.

Attentive launched in 2016 specifically as an ecommerce SMS platform. It has processed billions of messages and built a substantial toolset around subscriber acquisition, campaign management, and compliance. Klaviyo added SMS to its email platform in 2019, primarily as a channel that complements its existing email automation infrastructure.

Subscriber growth tools

Attentive's subscriber growth infrastructure is widely considered the best in the industry: - Two-tap mobile signup (opt-in without typing your number) - Attentive's Two-Tap technology achieves 2–5x higher conversion than standard keyword opt-in - Pop-up and embedded signup forms with A/B testing - Postback pixels that identify returning visitors who haven't opted in - Legal compliance pre-built into every signup touchpoint

Klaviyo's SMS opt-in tools are functional — forms that collect phone numbers alongside email, keyword opt-in flows, and integration with existing Klaviyo pop-ups. The tooling is adequate but Attentive's subscriber acquisition technology represents years of optimisation for this specific problem.

SMS subscriber growth is the primary lever in SMS marketing ROI. Attentive's subscriber acquisition advantage is its most defensible competitive advantage.

SMS campaign features

Two-way messaging — where customers can reply to your SMS and receive an intelligent response — is a growing capability. Attentive's two-way messaging infrastructure (including live agent integration) is more mature than Klaviyo's equivalent.

Compliance & deliverability

SMS marketing has strict legal requirements: TCPA compliance in the US, GDPR in Europe, and carrier-level guidelines that affect deliverability. Getting compliance wrong results in fines, spam filtering, and carrier blocking.

Attentive's compliance infrastructure is enterprise-grade — built to support brands with millions of subscribers across multiple jurisdictions. Their legal team actively monitors regulatory changes and updates the platform accordingly.

Klaviyo's compliance tooling covers the core requirements but is less sophisticated for enterprise-scale compliance management.

Pricing

Attentive does not publicly list pricing. Brands report paying $400–$2,000+/month depending on subscriber count and message volume. The pricing model typically combines a platform fee with per-message costs.

Klaviyo SMS pricing adds to existing Klaviyo email plan costs. SMS credits are purchased in blocks; pricing is approximately $0.01–$0.02 per SMS in the US. For most brands, adding Klaviyo SMS to an existing Klaviyo email account is the most cost-efficient entry point.

Verdict

Attentive for established brands actively investing in SMS as a primary marketing channel. If you have or plan to build a large SMS subscriber list (50K+), run regular SMS campaigns, and want dedicated subscriber growth infrastructure, Attentive's investment is justified.

Klaviyo SMS for brands already on Klaviyo who want to add SMS without managing a second platform. The convenience of unified email + SMS flows and reporting is a genuine advantage. Klaviyo SMS is the right starting point for brands where SMS is a secondary channel alongside email.

Frequently Asked Questions

What open rates should I expect from SMS marketing?

SMS open rates average 95–98% — significantly higher than email. However, SMS also has lower conversion rates per send because the channel is more intrusive and recipients are less tolerant of irrelevant messages. Click-through rates of 5–15% are typical for well-targeted SMS campaigns. Revenue per message varies widely by category, offer quality, and list quality.

Does Attentive or Klaviyo have better cart abandonment SMS?

Both platforms offer cart abandonment SMS that triggers when a known subscriber adds items to cart without purchasing. Attentive's implementation is more sophisticated for brands with high cart abandonment volume — including advanced segmentation of cart abandonment flows by cart value, product category, and customer LTV tier. For standard cart abandonment SMS, both platforms perform comparably.

Is SMS marketing cannibalising email performance?

No, based on most brand data. SMS and email reach different moments in the customer journey — SMS is immediate and action-oriented; email is considered and content-rich. Brands running both channels typically see email performance remain stable while SMS adds incremental revenue. The channels serve different consumption modes rather than competing for the same customer attention.

What is the best send frequency for SMS marketing?

2–4 SMS messages per month to your full subscriber list is the general industry guidance for promotional messages. More than 4-6 messages per month significantly increases opt-out rates unless the messaging is highly personalised and relevant. Automated flows (abandoned cart, post-purchase, win-back) can send more frequently because they're triggered by customer behaviour rather than broadcast to everyone.

How do I build an SMS subscriber list?

The fastest growth comes from: (1) adding a phone number field to your email popup with SMS consent language, (2) adding a dedicated SMS opt-in popup for mobile visitors, (3) running a campaign to your email list offering an incentive for SMS opt-in, and (4) including SMS opt-in language at checkout. Most brands find that SMS lists grow at 20–30% of the rate their email lists grow with comparable opt-in incentives.