Why this list looks the way it does
Three SMS platforms cover the realistic Shopify market in 2026: Postscript, Klaviyo, Attentive. We deliberately included Klaviyo here even though its primary category is email — when SMS is one channel inside a unified multi-channel CRM rather than a dedicated specialist surface, Klaviyo is the realistic pick for that operating shape. Pricing on every line below was verified directly on each vendor’s pricing page on May 30, 2026.
Two market shifts reshape this comparison vs 2024-2025 advice. Postscript introduced a new monthly platform fee in addition to per-message usage in 2026 — operator pushback is documented on the Shopify App Store. Klaviyo’s billing migrated from emails-sent to active profiles in February 2025, and the $10K/mo total-spend threshold triggers a mandatory Klaviyo One enterprise plan that adds 20% to the bill. Attentive does not publish entry pricing — a qualifying call is required, which is the enterprise-grade sales motion.
The three head-to-head pages worth reading
- Klaviyo vs Postscript for the bundled-channel vs SMS-specialist question
- Attentive vs Postscript for the multi-platform-enterprise vs Shopify-only-specialist question
- Attentive vs Klaviyo for the SMS-specialist vs multi-channel-CRM question
#1 — Postscript (winner for $50K-$500K MRR Shopify-first DTC)
Postscript is 100% Shopify-only SMS — the platform’s depth (45+ Shopify-specific segmentation filters, 130M+ Onsite Opt-in Network, Shopper AI for conversational commerce) is purpose-built for Shopify DTC operators where SMS is a real revenue channel. Starter at $25/mo + per-message usage ($0.015/SMS, $0.045/MMS US baseline) is published transparently. The 4x ROI guarantee is the explicit commercial commitment.
The honest caveat: Postscript introduced a new monthly platform fee in 2026 in addition to per-message usage, and longtime users have pushed back hard on the Shopify App Store (“I LOVED Postscript. And then this year they instituted a new monthly charge in ADDITION to charges per message sent”). For brands evaluating Postscript in 2026, model the actual 12-month cost against the 4x ROI guarantee on your own list, and verify the trial-conversion terms in writing. The capability is real and best-in-category for Shopify-native SMS. The pricing-model frustration is also real.
Postscript runs an active affiliate program on the PartnerStack platform.
#2 — Klaviyo (winner for stores under $50K MRR or unified multi-channel CRM)
Klaviyo’s SMS is bundled inside the multi-channel B2C CRM with email, WhatsApp, RCS, push, and voice — billed on active-profile count rather than per-message. For Shopify stores not yet at $50K MRR or already running email on Klaviyo and wanting SMS managed alongside it, this is the pragmatic pick. The free tier includes 150 SMS credits, enough to test SMS-flow viability without a second platform contract.
Honest caveats per content-flags. First, the “20% commission / 90-day cookie” line that third-party affiliate directories repeat does not appear on Klaviyo’s official Partner Program page; the actual structure is tiered BASIC→ELITE with quarterly payouts. Second, above ~$10K/mo total spend, Klaviyo One enterprise becomes mandatory and adds 20% to the bill — model your 12-month projected spend against this threshold before committing. Third, billing changed from emails-sent to active profiles on February 18, 2025, which means sticky lists pay for inactive contacts.
For dedicated SMS depth at $50K+ MRR, migrate to Postscript later — the Klaviyo SMS pilot data helps defend the move. Klaviyo runs an active affiliate program with the tiered Partner Program structure.
#3 — Attentive (winner for multi-platform or enterprise contract negotiation)
Attentive does not publish entry pricing on its website — a qualifying call is required, with entry likely in the $1k-$2k/mo range per third-party estimates and custom enterprise tiers above that. The deciding case for Attentive over Postscript or Klaviyo is multi-platform operations: Attentive scales across Shopify, Salesforce Commerce Cloud, Magento, and BigCommerce. Postscript does not exist outside Shopify; Klaviyo’s multi-platform depth varies by integration.
For Shopify-only DTC brands at $500K+ MRR considering enterprise SMS, Attentive’s qualifying-call sales motion + enterprise account management may justify the platform breadth premium over Postscript’s published-pricing specialist depth — verify directly during sales evaluation against your specific channel mix and account-management expectations.
Attentive does not run a publicly-active affiliate program at the time of verification.
The honest verdict
Pick Postscript when Shopify-first DTC operations + SMS as a real revenue channel + published pricing transparency matter, and your 12-month spend math survives the 2026 monthly-platform-fee + per-message billing shift.
Pick Klaviyo when SMS is a supplementary channel inside a unified multi-channel CRM, you’re below $50K MRR (or projecting under the $10K/mo total-spend threshold for 12+ months), and consolidating email + SMS into one vendor reduces operating overhead.
Pick Attentive when multi-platform operations (Shopify + at least one of Salesforce CC / Magento / BigCommerce) or enterprise contract negotiation are the actual operating need.
For the three head-to-head pages with verified-pricing tables and segmented use-case verdicts, see Klaviyo vs Postscript, Attentive vs Postscript, and Attentive vs Klaviyo.