Postscript vs Klaviyo SMS (2026): Which SMS Tool for Your Shopify Store?
Postscript and Klaviyo SMS compared for Shopify stores: monthly fees, per-message prices, minimums, support and when an SMS-only tool beats SMS inside your email platform.
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Short answer: If SMS is a modest add-on to your email program, Klaviyo SMS keeps everything in one profile and one bill. If SMS is a core revenue channel, Postscript – an SMS-only platform built for Shopify – offers lower published per-message rates at volume and SMS-specific tools. Many stores use both: Klaviyo for email, Postscript for SMS.
Prices from each vendor’s pricing page and Shopify App Store listing (Postscript checked October 21, Klaviyo October 22, 2026), in USD. This comparison is based on published information, not a hands-on test.
Side-by-side
| Postscript | Klaviyo SMS | |
|---|---|---|
| What it is | SMS-only platform for Shopify | SMS add-on inside Klaviyo’s email platform |
| Monthly fee | Starter $0; Growth $100; Professional $500; Enterprise custom | Billed with your Klaviyo account; Shopify listing shows SMS from $15/month for up to 1,250 credits |
| Price per US SMS | $0.009 / $0.008 / $0.007 (Starter / Growth / Professional) | Not listed per message; credit add-on (Shopify listing from $15/mo for 1,250 credits incl. carrier fees) |
| Price per MMS | $0.045 / $0.03 / $0.024 | Uses more credits than an SMS |
| Minimum | $49 monthly spend on Starter | – |
| Free option | 30-day free trial on every plan | Free plan includes $5 of mobile messages a month |
| Not yet (waitlist) | Yes – same platform | |
| Support | Live chat and email from Growth; priority support on Professional | Paid plans: 24/7 email, live chat on weekdays |
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”–” = not stated on the vendor’s site. Klaviyo notes that its rates include carrier fees where applicable, and the number of credits a message uses depends on destination and message type, so model your volume in Klaviyo’s calculator.
Cost: it depends on volume
Using Postscript’s published rates, a store sending 10,000 US SMS a month on Starter pays about 10,000 × ($0.009 + roughly $0.0033 in carrier fees) ≈ $123, above the $49 minimum (worked example in our Postscript review). Growth adds a $100 fee for a lower rate and better support, so at this volume it costs more, not less – Growth and Professional pay off through features and support, or at much higher volumes.
For Klaviyo, SMS is a credit-based add-on with no listed per-message rate; its Shopify listing starts at $15/month for 1,250 credits including carrier fees, and the exact credit use per message varies, so get a quote for your country mix before comparing totals.
Features
Postscript is built only for SMS: campaigns, automations, unlimited segments, a toll-free number and opt-in keywords on Starter, with more keywords and support on Growth and API access and enhanced analytics on Professional. Enterprise adds a dedicated success manager and product recommendations.
Klaviyo SMS shares one customer profile with your email, so a flow can send an email and then a text, and segments can mix email and SMS behavior. You manage both channels, and see their results, in one place.
Which should you choose?
Pick Postscript if:
- SMS already drives (or you expect it to drive) a meaningful share of revenue.
- You send enough texts that per-message rates and SMS-specific tools matter.
- You’re happy to keep a separate email platform (including Klaviyo).
Stay with Klaviyo SMS if:
- You already use Klaviyo for email and send occasional texts.
- One profile, one bill and one reporting view matter more than the lowest rate.
Consider Omnisend if you want email and SMS together for less – see best SMS marketing apps for Shopify and Omnisend vs Klaviyo.
See Postscript plansKey takeaways
- Postscript is SMS-only and built for Shopify; Klaviyo sells SMS as an add-on inside its email platform.
- Postscript Starter has no monthly fee but a $49 monthly minimum spend and $0.009 per US SMS; Growth ($100/month) and Professional ($500/month) lower the rate to $0.008 and $0.007.
- Klaviyo no longer lists a per-message SMS rate; SMS is a credit-based add-on, and its Shopify listing shows SMS from $15/month for up to 1,250 credits including carrier fees.
- Postscript lists a Klaviyo integration, so many stores run Klaviyo for email and Postscript for SMS.
- If SMS is a small add-on, keeping it inside Klaviyo is simpler; if SMS is a core revenue channel, Postscript's SMS-specific features and volume rates are the reason to add it.
Frequently asked questions
Is Postscript cheaper than Klaviyo SMS?
Per US SMS, Postscript's published rates ($0.009 on Starter down to $0.007 on Professional) are published per message, while Klaviyo quotes SMS as a credit-based add-on without a listed per-message rate, so compare a Klaviyo quote for your volume. But Postscript Starter has a $49 monthly minimum and the lower rates come with $100 or $500 monthly fees, so total cost depends on your volume.
Can I use Postscript with Klaviyo?
Yes. Postscript lists Klaviyo among its integrations, so you can keep Klaviyo for email and use Postscript for SMS.
Does Postscript do email?
Not yet. When we checked, Postscript's email product was listed as a waitlist, so you still need an email platform.
Does Postscript have a free trial?
Yes. Postscript says every plan starts with a 30-day free trial.