Comparison

Klaviyo vs Postscript

A detailed breakdown of Klaviyo and Postscript for e-commerce sellers. Last updated 2026-04-01.

Quick verdict

Klaviyo scores highest overall (8/10), but the best choice depends on your use case.

Klaviyo:Shopify store owners serious about email and SMS marketing
Postscript:Shopify stores that want SMS as a dedicated revenue channel, not just a bolt-on to email
Klaviyo8/10
Postscript7.5/10
Starting priceFree tierFree tier
Overall score
8/10Best
7.5/10
Ease of use
7/10
8/10Best
Value for money
8/10Best
8/10Best
Shopify
10/10Best
10/10Best
Amazon
2/10Best
0/10
Platforms
Shopify
Shopify
Free trialYesYes

How they compare

What is Klaviyo?

Klaviyo is the dominant email and SMS marketing platform for Shopify stores. Its deep Shopify integration means it pulls in order data, browsing behaviour, and customer profiles automatically, giving you segmentation capabilities that generic email tools cannot match. The AI features handle subject line generation, send-time optimisation, and predictive analytics.

What is Postscript?

Postscript is an SMS marketing platform built exclusively for Shopify. Unlike Klaviyo and Omnisend which treat SMS as an add-on to email, Postscript treats it as a dedicated revenue channel with its own AI tools, automation engine, and conversational commerce features. Over 18,000 Shopify brands use Postscript, including Dr. Squatch and Brooklinen, and the platform reports an average 34x ROI on SMS spend.

Key differences

  • Klaviyo scores 8/10 overall versus 7.5/10 for Postscript.
  • Klaviyo is significantly stronger for Amazon sellers.

Klaviyo

+Best-in-class Shopify integration
+AI subject line generator
+Powerful segmentation
+Free up to 250 contacts
-Gets expensive as list grows
-Steep learning curve
-Amazon integration is limited

Postscript

+Built exclusively for Shopify with deep integration
+AI-powered Infinity Testing across thousands of message variants
+Two-way conversational commerce with Shopper AI
+Free Starter plan with pay-per-message pricing
-Shopify only, no other platforms supported
-US and Canada only for SMS delivery
-Per-message costs add up at high volume
-Revenue attribution can overcount

Which is best for you?

Choose Klaviyo if...

The gold standard for Shopify email marketing. The AI features are a nice bonus, but the real value is in the data-driven segmentation.

Choose Postscript if...

The specialist SMS platform for Shopify. If SMS is a serious revenue channel for your store, Postscript's AI testing and conversational commerce features give it an edge over the SMS add-ons in Klaviyo and Omnisend.

Note: Both tools cover Email Marketing. The best pick depends on your budget and whether you prioritise ease of use or depth of features.

Our verdicts

Klaviyo -- 8/10

The gold standard for Shopify email marketing. The AI features are a nice bonus, but the real value is in the data-driven segmentation.

Postscript -- 7.5/10

The specialist SMS platform for Shopify. If SMS is a serious revenue channel for your store, Postscript's AI testing and conversational commerce features give it an edge over the SMS add-ons in Klaviyo and Omnisend.