SMS Marketing AI Tools 2026: Postscript vs Attentive vs Klaviyo for DTC
Every CRM manager I know has been through the same exercise this quarter. Yotpo SMS sunset on December 31, 2025, and Postscript pushed Shopper to GA early in 2026. So now you have to re-pick your SMS stack whether you wanted to or not. This piece is not a feature checklist. It is a buying guide built around GMV tier and existing stack, which is what actually decides the answer.
What the three tools actually look like in 2026
Postscript led the year with Shopper, a conversational SMS agent that handles purchase conversations in your brand voice. The official number is a 20% average revenue lift on SMS. Sitting behind it is Infinity Testing, which runs thousands of copy variants in parallel and keeps the winners. Postscript is Shopify-native end to end, and its Theme Editor SMS capture widget is the deepest of the three. Pricing starts at 100 dollars a month plus send usage.
Attentive expanded AI Pro for Email plus SMS through Q1 and Q2 2026. Audiences AI is credited with a 40% revenue lift, and abandonment journeys add another 20% on top. Positioning is clear: brands doing 20 million dollars or more in GMV. Pricing is custom and usually lands above 1000 dollars a month. Enterprise SSO plus the CCPA and TCPA compliance workflow is the cleanest of the three.
Klaviyo kept its all-in-one thesis and is folding SMS deeper into its data model. SMS AI right now focuses on send-time optimization and flow copy generation. The conversational agent is in beta and will ship alongside the Composer agent later in 2026. The real advantage is that SMS, email, reviews, and mobile push share one customer profile. For SMB to mid brands that do not want to stitch vendors together, Klaviyo removes glue work. Bundled plans start at 45 dollars a month for email plus SMS.
Decision matrix: one table to place each tool
| Criterion | Postscript | Attentive | Klaviyo |
|---|---|---|---|
| Shopify native | Yes | Standard integration | Yes |
| Conversational agent | GA in 2026 | In test | Beta |
| Cross-channel (email + SMS) | SMS only | Email + SMS unified | Email + SMS + reviews unified |
| Compliance workflow | Standard 10DLC | 10DLC plus SSO, CCPA, TCPA | Standard 10DLC |
| Theme Editor widget | Deep capture widget | Standard | Medium |
| Price tier | SMB and up | Mid to Enterprise | SMB to Mid |
| Best for | Shopify-first, SMS-led | Brands over 20M GMV | All-in-one SMB to Mid |
The row that matters most is cross-channel. If email already lives in Klaviyo and you do not want to introduce a separate SMS vendor, Postscript only pays off when SMS is a primary channel rather than a supporting one.
Pricing: look past the starting number
| Tool | Starting monthly | Conversational agent | Revenue tier fit |
|---|---|---|---|
| Postscript | 100 dollars plus usage | Included (Shopper GA) | 50K to 3M monthly revenue |
| Attentive AI Pro | Custom, typically 1000 dollars plus | In test for AI Pro customers | 2M monthly revenue and up |
| Klaviyo | From 45 dollars (email + SMS bundle) | Beta, GA later in 2026 | 10K to 2M monthly revenue |
Your real bill is dominated by send volume. Postscript charges per message at roughly 0.01 to 0.03 dollars depending on carrier and destination. Attentive usually rolls usage into the annual contract, but the floor is high. Klaviyo uses an SMS credit model that tends to be kindest at lower volumes. Pull the last six months of sends from your current provider and model all three against that number — the starting price often flips once you plug in real volume.
Yotpo SMS sunset: how to pick a migration path
Q2 2026 became the migration window for the whole SMS category because Yotpo SMS went dark at the end of last year. If you were on Yotpo SMS because of Yotpo Reviews and Loyalty, and you do not want to break that bundle apart, Klaviyo is the cleanest landing. Klaviyo integrates natively with Reviews and supports third-party loyalty, and subscriber lists map over via CSV if you carry the original opt-in timestamp and source. Skip those fields and 10DLC review will bounce you.
If you run Shopify and SMS is a growth driver rather than a nice-to-have, Postscript Shopper is worth the bet in 2026. Shopify-native migration of historical orders and customer tags is essentially free, and the Theme Editor widget drops in to replace the Yotpo capture script. Infinity Testing pays off fastest on abandonment flows where you can run variant tests against live traffic.
If you are already past 20M in GMV with separate email and SMS teams, Attentive AI Pro is the right contract even though it costs more. Audiences AI produces measurable lift on mid and enterprise catalogs, and the compliance workflow saves weeks of legal review. Plan for a 6 to 8 week migration — the tool swap is the easy part, the enterprise compliance handoff is not.
How to pick based on tier and stack
Three lines to land this. Under 2M annual revenue, Shopify store, and you want one platform for email and SMS: pick Klaviyo and ride Flow AI plus send-time optimization until Composer agent goes GA. Between 500K and 3M annual revenue with SMS as a core channel and someone in-house running SMS full-time: pick Postscript and lean into Shopper. Over 2M monthly revenue with dedicated email and SMS teams and hard compliance requirements: sign Attentive AI Pro. One thing no tool fixes is the quality of your opt-in list and the placement of your capture points. The AI agent is an amplifier. Clean the signal before you amplify it.
Takeaways
The three tools picked distinct lanes in 2026. Postscript went deep on conversational agents and Shopify integration. Attentive doubled down on cross-channel AI and enterprise compliance. Klaviyo stayed the course on one unified data model. The right pick falls out of GMV tier plus existing stack, not a feature grid. The Yotpo migration window is still open. The earlier you move, the less pain you take on 10DLC review and opt-in cleanup.
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