Klaviyo SMS vs Postscript vs Attentive: how to choose for a Shopify brand

Klaviyo SMS vs Postscript vs Attentive: how do they compare?

Everything below comes from each company's own pages as of October 13, 2026, listed in Sources. Prices change, so check the live pages with your real numbers.

A few notes on reading that table:

• Postscript's rates are US and Canada only. Its pricing page says so in the footnote.
• Klaviyo splits long texts. Its help center says a message over the character limit is automatically split into multiple segments, and each one costs.
• Postscript plans add support as you go up. Growth adds live chat and email support, Professional adds priority support, and Enterprise adds a dedicated customer success manager.

How much would each one cost me?

Only Postscript publishes enough to do the math from its page alone. Here's a hypothetical using its listed US rates plus its listed average carrier fee of $0.0033 per SMS.

Say you send 20,000 single-segment texts a month:

• Starter: 20,000 × ($0.009 + $0.0033) = about $246 a month.
• Growth: $100 + 20,000 × ($0.008 + $0.0033) = about $326 a month.

Growth only pays for itself on rates once you send more than about 100,000 texts a month, since it saves $0.001 per text against a $100 fee. Professional's extra $400 over Growth breaks even at about 400,000 texts a month on the same math.

For Klaviyo and Attentive, you'll need a quote or your account's billing page. With Klaviyo, the thing to plan for is the monthly plan spend: pick a plan close to what you'll actually send, because unused spend doesn't carry over. Klaviyo's help center suggests downgrading if you consistently have spend left at the end of the month.

Which SMS tool would I pick?

Klaviyo. I run SMS in Klaviyo because it keeps email and SMS in the same house. When both channels sit in one account, attribution is a lot less confusing. You're not trying to reconcile two tools that each want credit for the same order, and your flows, segments and reporting all live in one place.

You should know my bias: Shopify plus Klaviyo is the setup I know best, and I trust Klaviyo because their stuff connects with everything. Postscript is the most transparent of the three on price, with listed per-message rates, no prepaid balances and a free 30-day trial on all plans. Attentive also sells text and email together, on a custom quote, so the same-house argument can apply there too if you're starting fresh.

If you're still weighing them, here are the questions I'd work through, in order:

1. Do you want one tool or two? If your email runs in Klaviyo, Klaviyo SMS keeps consent, segments, flows and reporting for both channels in one place. With a separate SMS tool, ask how it shares subscribers, orders and suppressions with your email platform, and how you'll keep people from getting the same message twice on the same day.
2. How do you want to be billed? A set monthly spend (Klaviyo), pay after you send with a minimum (Postscript Starter), or a custom quote (Attentive). Set spend is predictable but use-it-or-lose-it. Pay-as-you-go flexes with your volume.
3. How many texts will you really send? Write down your flows and campaigns per month, multiply by your SMS list, and add MMS and long messages. Then price that number on each platform. Be honest about it, since a set monthly spend you don't use is money gone.
4. How much help do you need? If nobody on your team will own SMS, support levels matter. Postscript ties support to plan tier on its pricing page. Ask Klaviyo and Attentive what's included at your size.
5. What are the contract terms? Attentive's pricing page doesn't mention contract terms, and Postscript covers it in an FAQ on its pricing page. Either way, get length, cancellation and minimums in writing before you sign.
6. What Shopify data do you need? If you want texts triggered by checkout behavior or segments built on purchase history, confirm the tool syncs exactly what you need, and test it before you move your list.

If email isn't working yet, none of this is the first decision. I'd start with should I add SMS marketing, which covers when texts are worth it and the consent basics.

What should you check before switching SMS tools?

Before you switch:

• Confirm consent records move with the numbers. Klaviyo's help center notes that its Shopify consent sync only covers people subscribing to SMS in Shopify for the first time, and existing subscribers need a separate process.
• Map every flow. Cart, checkout, restock and reorder texts all need to be rebuilt and tested before you turn the old ones off.
• Re-check your numbers. Compare revenue per subscriber and opt-outs before and after.

FAQ

WRITTEN BY Jack White

Founder of Bardown Digital, a Chicago-based Klaviyo email and retention agency for Shopify brands. He's worked with brands doing $500K to $100M a year, with $100M+ in email-attributed revenue across them.

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