Klaviyo vs Postscript

Both are AI-driven retention tools for e-commerce, but Klaviyo runs email and SMS together across hundreds of integrations while Postscript is an SMS-only platform built exclusively for Shopify.

Quick answer: Klaviyo is the better choice for e-commerce and marketing teams that want email and SMS together with predictive analytics and fine-grained, behavior-based segmentation.; Postscript is the better choice for shopify and Shopify Plus brands focused on SMS that want on-brand AI copy, a sales-driving reply assistant, and compliance handled for them..

Last updated June 21, 2026

The verdict

Pick Klaviyo if you want email and SMS in one platform with deep data and segmentation. It pairs unified customer profiles with predictive analytics like lifetime value and churn risk, builds segments from a plain-language description, and runs AI across content, send-time optimization, and agents for both marketing and customer support. With 350-plus integrations it suits marketing teams that want to slice their list finely and act on behavior, not just send the same blast to everyone. The trade-off is cost: it scales hard with your list and bills SMS separately on top of email.

Pick Postscript if SMS is your focus and your store runs on Shopify. It is built only for Shopify and Shopify Plus, so it reads order and customer data directly and personalizes texts around real products and purchase history. Its AI plan adds a Brand Center that trains on your store voice, Infinity Testing for message variants at scale, and a Shopper assistant that answers product questions over text and pushes shoppers to checkout. A built-in compliance engine and an in-house legal team handle opt-ins, opt-outs, and carrier rules, which lowers the risk for brands new to texting. Just note the AI features sit on a separate plan, and Postscript is only useful if you are on Shopify. Many teams pair the two, using Klaviyo for email and Postscript for SMS.

Klaviyo

Freemium

Klaviyo is an email and SMS platform made for online stores, pairing customer data with automation, segmentation, and flows. Its AI drafts content, builds segments, predicts behavior, and picks send times, all tied to deep Shopify integration.

Best for: E-commerce and marketing teams that want email and SMS together with predictive analytics and fine-grained, behavior-based segmentation.

Try Klaviyo →

Postscript

Freemium

Postscript is an SMS marketing platform made for Shopify, covering list growth, campaigns, automations, and two-way replies. Its AI plan adds on-brand message generation, large-scale testing, and a 1:1 shopping assistant.

Best for: Shopify and Shopify Plus brands focused on SMS that want on-brand AI copy, a sales-driving reply assistant, and compliance handled for them.

Try Postscript →

Side-by-side comparison

	Klaviyo	Postscript
Pricing	Freemium	Freemium
Starts at	USD 20.00	USD 0.00
Free trial	Yes	Yes
Rating	4.4	4.6

Pricing compared

Both are freemium and scale with volume. Klaviyo has a free plan for up to 250 profiles with a monthly email cap, paid Email plans from $20/month priced by active profiles, and Email + SMS starting around $35/month with SMS volume billed separately; large senders move to the enterprise Klaviyo One tier. Postscript uses platform fees plus per-message carrier costs: Starter has a $0 platform fee with a monthly minimum spend, Growth is $100/month, and Professional is $500/month, with the Postscript AI plan and Enterprise priced separately. Klaviyo's $0 free plan and $20 email entry are the cheaper start for email; Postscript's free trial includes $100 in messaging credit.

Features compared

Klaviyo centers on email and SMS flows (welcome, abandoned cart, post-purchase), AI content generation with a Marketing Agent, predictive analytics for lifetime value and churn, AI segmentation from plain-language descriptions, per-recipient send-time optimization, and deep Shopify integration across 350-plus connectors, plus a Customer Agent for support and sales conversations. Postscript is Shopify-native SMS only, covering campaigns and automations, a Brand Center that trains the AI on your store voice, Infinity Testing that generates and tests many on-brand variants, a Shopper 1:1 reply assistant that drives checkout, and a built-in compliance engine for opt-ins, opt-outs, and carrier rules. Klaviyo is the broader multi-channel platform with predictive data depth; Postscript goes narrow and deep on SMS for Shopify.