Shopify app comparison · updated Aug 26, 2026
Klaviyo vs Postscript
Compare Klaviyo and Postscript for Shopify using current ratings, review activity, pricing, features, and OngoingAI-observed adoption.
Klaviyo
Klaviyo: Email Marketing & SMS
Build email marketing, SMS, and WhatsApp campaigns powered by AI to grow ecommerce sales.
- Rating
- 4.70
- Reviews
- 3,007
- Review growth · 30d
- +54 · +1.8%
- Pricing
- Free to install
- Years on Shopify
- 14
- Stores observed
- 34,965
Postscript
Postscript SMS Marketing
Create and execute SMS programs to drive incremental revenue by engaging customers via text message
- Rating
- 4.70
- Reviews
- 1,146
- Review growth · 30d
- +1 · +0.1%
- Pricing
- Free to install
- Years on Shopify
- 8
- Stores observed
- 1,950
Our read
Klaviyo has the stronger observed market footprint in OngoingAI's data — it appears on 17.9× more tracked stores and carries 2.6× the App Store review depth. Ratings and recent review growth are closer.
- Rating
- Level4.7 vs 4.7
- Review growth
- Klaviyo faster+1.8% vs +0.1%
- Review depth
- Klaviyo2.6× more reviews
- Observed adoption
- Klaviyo17.9× more tracked stores
Review trajectory
How each app's Shopify reviews are moving.
Daily App Store review counts since we began tracking — who's gaining reviews fastest, who holds the larger base, and how the race is developing.
Klaviyo leads total reviews and is adding them fastest over the tracked window.
Reviews each app has gained since the start of this tracking window. · Tracking window · Aug 10 – Aug 26, 2026
Head-to-head
The signals, side by side.
Each row reads straight from the live App Store listing and OngoingAI’s census. The Difference column states the gap — not a buyer recommendation.
| Dimension | Klaviyo | Postscript | Difference |
|---|---|---|---|
| Rating | 4.70 | 4.70 | Level |
| Reviews | 3,007 | 1,146 | Klaviyo 2.6× |
| Review growth · 30d | +54 · +1.8% | +1 · +0.1% | Klaviyo faster |
| Listed pricing | Free to install | Free to install | Not directly comparable |
| Years on Shopify | 14 | 8 | Klaviyo +6y |
| Stores observed | 34,965 | 1,950 | Klaviyo leads |
Which fits your requirements?
Choose by what you actually need.
Choose Klaviyo if…
- You need email marketing
- You need email campaigns
- You need sms campaigns
- Recent review-growth signals matter to you
Choose Postscript if…
- You need sms notifications
- You need pop-up builder
- You need triggers
Tied to observable requirements only — listed capabilities, ratings, review growth, adoption and price. It doesn’t assert usability or support quality.
Feature differences
What Klaviyo and Postscript each do that the other doesn’t.
They cover largely the same ground — 5% of listed capabilities overlap. The decision material is the rest: what each lists that the other doesn’t.
Klaviyo only
38
- Email marketing
- Email campaigns
- SMS campaigns
- Push notifications
- Newsletters
- Pop-ups
- Forms
- Discounts
- Promotions
- Upsell emails
- Cross-sell emails
- Cart emails
- Checkout emails
- Exit intent
- Browse abandonment
- Welcome emails
- Follow-up emails
- Price drop emails
- Back-in-stock emails
- Win-back emails
- Product recommendations
- Drip campaigns
- Subscriptions
- Product reviews
Postscript only
14
- SMS notifications
- Pop-up builder
- Triggers
- A/B testing
- SMS marketing
- Compliance
- Personalized messages
- Scheduled messages
- Two-way messaging
- Segmentation
- Opt-in
- Cart recovery
- Welcome messages
- One-time password (OTP)
2 shared capabilities
- Abandoned cart
- Templates
Observed adoption
Who actually runs each, on real stores.
The stores OngoingAI’s weekly census observes running each app, and the platform each skews toward — observed presence, not vendor-reported install totals.
Klaviyo
34,965
stores observed
Skews Shopify · 89%
Postscript
1,950
stores observed
Skews Shopify · 100%
Scope
What this comparison measures.
What it measures
Shopify App Store ratings, review counts and 30-day review growth, listed pricing and capabilities, category data, and OngoingAI-observed storefront adoption for Klaviyo and Postscript.
What it doesn’t
Hands-on usability, customer-support quality, deliverability, merchant sentiment from review text, or revenue impact. We draw a sharp line around what we can observe.
Methodology
Where the numbers come from.
Ratings, review counts, pricing, and categories come from the live Shopify App Store listing, refreshed daily. Review growth compares the observed snapshots across the trailing 30-day window. “Stores observed” and the platform split come from OngoingAI’s weekly storefront census — the real stores running each app, not the listing’s claimed totals. Comparison generated Aug 26, 2026.
See who’s switching — as it happens.
Track app adoption on live ecommerce stores. Find merchants running Klaviyo or Postscript, follow stack changes, and see when a store installs, removes, or replaces an app.