Postscript SMS Review: An Honest Take (And Why We Recommend Klaviyo Instead)

Last Updated: February 2026

Postscript is a dedicated SMS marketing platform for Shopify stores. It does what it claims to do — send text messages to your customers. But after working with dozens of ecommerce brands on their retention marketing, we don't recommend it.

Our recommendation: If you're already using Klaviyo for email (and you should be), use Klaviyo SMS instead. Having email and SMS in one platform is significantly easier to manage, gives you better data, and avoids the attribution mess that comes with running two separate systems.

This article covers what Postscript does, why we prefer Klaviyo SMS, and — most importantly — how to actually use SMS effectively regardless of which platform you choose.

What Postscript Does

Postscript is a Shopify-focused SMS marketing platform. It handles the core functions you'd expect: collecting phone numbers, sending campaigns, building automated flows, and segmenting your audience. It integrates directly with Shopify and has features like two-way messaging and AI-powered auto-replies.

The platform works. If you only need SMS and don't use Klaviyo for email, Postscript is a reasonable choice. But that's rarely the situation we see.

Why We Recommend Klaviyo SMS Instead

If you're already using Klaviyo for email — and most serious ecommerce brands are — adding a separate SMS platform creates unnecessary complexity. Here's why we tell clients to use Klaviyo SMS:

1. Everything in One Place

Managing email and SMS in separate platforms means double the work: building segments twice, creating flows twice, checking analytics in two dashboards. With Klaviyo SMS, you build once. Your segments, flows, and customer data all live in the same place.

2. Better Attribution

When you run Klaviyo for email and Postscript for SMS, both platforms will claim credit for the same sales. Add up the revenue from both dashboards and you'll see a number higher than your actual revenue — because they're both attributing the same purchases.

With everything in Klaviyo, attribution is still generous (all email/SMS platforms are), but at least you're looking at one source of truth instead of two conflicting reports.

3. Easier Segmentation

Your best SMS segments are based on email and purchase behavior: customers who opened your last email, people who bought in the last 30 days, subscribers who haven't purchased yet. With Klaviyo SMS, this data is already there. You don't have to sync it from another platform or hope the integration doesn't break. Use our Audience Builder to map out your segmentation strategy.

4. Coordinated Flows

The real power of SMS is using it alongside email in the same flow. Abandoned cart? Send an email first, then an SMS 2 hours later if they didn't convert. With Klaviyo, this is one flow. With Postscript, you're building parallel flows and hoping the timing works out. Use our Flow Builder to design integrated email + SMS sequences.

How to Actually Use SMS (Regardless of Platform)

Here's what most brands get wrong about SMS: they try to use it like email. SMS is not a brand-building channel. It's a notification channel.

People don't want to receive text messages about your brand story or your founder's journey. They want timely, relevant notifications about things that matter to them right now.

What SMS is Good For

• Abandoned carts and checkouts: "Hey, you left something behind — grab it before it's gone"
• Shipping notifications: "Your order just shipped! Track it here"
• Flash sales and time-sensitive offers: "24 hours only: 20% off everything. Shop now"
• Back in stock alerts: "That product you wanted is back — limited quantity"
• Order delivery updates: "Your package is out for delivery today"

What SMS is NOT Good For

• Brand storytelling or educational content
• Long-form product descriptions
• Weekly newsletters
• Anything that requires more than 2-3 sentences

Use email for storytelling and nurturing. Use SMS for urgency and notifications. They work together, not as substitutes for each other.

SMS Examples That Work

Here are examples of SMS messages that actually convert:

Abandoned Cart

Hey [First Name], you left [Product Name] in your cart. Grab it before it's gone → [Link]

Still thinking about it? Your [Product Name] is waiting for you. Don't let it disappear → [Link]

Shipping Notification

Your [Brand Name] order just shipped! Track it here → [Link]

Heads up: your package is out for delivery today 📦

Flash Sale

FLASH SALE: 20% off everything. 24 hours only. Shop now → [Link]

Notice the pattern: short, urgent, one clear action. That's what works for SMS.

Common SMS Mistakes We See

The biggest SMS mistakes aren't about platform choice — they're about strategy:

1. Not Using It At All

Many brands collect phone numbers and then never text them. They have the list, they have the platform, but they're afraid of annoying people. Meanwhile, they're leaving money on the table. SMS has higher open rates than email — use it.

2. Not Integrating With Email Timing

Sending SMS and email as completely separate channels is a missed opportunity. They should work together. If someone gets an abandoned cart email and doesn't open it, follow up with an SMS. If someone just got an email campaign, don't send them the same offer via SMS 10 minutes later.

3. Treating It Like Email

We see brands sending paragraph-long SMS messages with multiple links and calls to action. That's not how people use text messages. Keep it short, keep it urgent, one action per message.

If You Still Want to Use Postscript

If you're not using Klaviyo for email and just need a standalone SMS platform, Postscript is a reasonable option. Here's the quick overview:

• Pricing: Starts at $25/month with credit-based messaging. They offer a 30-day trial with $1,000 in credits.
• Setup: Shopify app store installation, straightforward onboarding.
• Features: Automated flows, segmentation, two-way messaging, AI auto-replies.
• Support: Generally well-reviewed for responsiveness.

For current pricing details, check Postscript's pricing page.

But again — if you're using Klaviyo for email, just use Klaviyo SMS. The integration benefits outweigh any specialized features Postscript offers.

Bottom Line

Postscript works as a standalone SMS platform, but we don't recommend it for most brands. If you're using Klaviyo for email — which you should be — use Klaviyo SMS instead. You'll get cleaner data, easier segmentation, better attribution, and half the management overhead.

More importantly: the platform matters less than the strategy. Use SMS for notifications and time-sensitive offers, not brand storytelling. Keep messages short. Integrate with your email timing. And actually send — the biggest mistake is collecting numbers and then being afraid to use them.

For more on building a complete retention strategy, read our guide on what Klaviyo does and how to use it effectively.

Frequently Asked Questions

Should I use Postscript or Klaviyo SMS?

If you're using Klaviyo for email, use Klaviyo SMS. Managing both channels in one platform simplifies segmentation, improves attribution accuracy, and reduces management overhead. Only consider Postscript if you're not using Klaviyo at all.

How often should I send SMS messages?

Less frequently than email. SMS should be reserved for time-sensitive notifications: abandoned carts, shipping updates, flash sales, back-in-stock alerts. Most brands send 2-4 SMS campaigns per month plus automated flows.

What's a good SMS opt-in rate?

SMS lists are typically 10-30% the size of email lists. That's normal — SMS requires explicit consent and people are more protective of their phone numbers. Focus on quality over quantity; SMS subscribers tend to be higher-intent.

Can I use SMS for brand storytelling?

No. SMS is a notification channel, not a content channel. People don't want paragraphs of brand content in their text messages. Use email for storytelling and nurturing. Use SMS for urgency and transactional updates.

What flows should I set up first for SMS?

Abandoned cart and abandoned checkout (these are different flows). Then shipping/delivery notifications. Then welcome series (SMS only if they opted in via SMS). These cover the highest-impact use cases for most ecommerce brands.