Pick Klaviyo if you want email, SMS and customer data in one account and you can live with contact-based billing. Pick Attentive if SMS is your lead channel and you want compliance tooling and support bundled across SMS, email, RCS and push. Pick Postscript if you want SMS priced per message with published rates, and you are happy to run email elsewhere. Pick Listrak if you want one vendor across email, SMS, push and onsite with identity resolution, and Mailchimp if email is a newsletter plus a few automations rather than your main growth channel.
At a glance
 Klaviyo |  Attentive |  Postscript |  Listrak |  Mailchimp | |
|---|---|---|---|---|---|
| Built for | B2C brands of all sizes, with retail, wellness and enterprise pages | Retail and ecommerce plus food and beverage, travel, fitness and other industries | Ecommerce brands on Shopify, from first SMS program to main revenue channel | Retailers and ecommerce brands, including Shopify Plus; certified Shopify Plus Partner | Growing businesses, with ecommerce, small business and mid market pages |
| What else it sells | Reviews app, helpdesk, customer data platform, AI campaign and service agents | Email, RCS, push and AI campaign tools alongside SMS | RCS, email, an AI plan bundle, and Postscript Plus managed service | Data platform, AI recommendations, journey orchestration, onsite experience builder | Transactional email, landing pages, automation flows, SMS as an Essentials add-on |
| Pricing shape | Free plan, then monthly tiers by contacts for email and by credits for SMS | Modular, based on messages, list size, channels and AI tools; no amounts published | Monthly tiers plus per-message rates and carrier fees, published on the pricing page | Free to install on the App Store, external charges billed by the vendor | Free tier then three paid tiers priced by contacts, with send overages |
| Where it is strongest | One account for email, SMS, data and segmentation, with predictive analytics and send time optimization | SMS and cross-channel sends with TCPA tools included on every plan | SMS economics: pay after sending, no prepaid balances, expiring credits or overages | Single customer profile across email, SMS, push, web and onsite personalization | Email with integrations beyond Shopify and audience reporting |
| Most common reason brands leave | Billing tied to contacts rather than sends, plus deliverability and support friction | Cost at scale, and attention split across channels beyond SMS | A program sent only occasionally, or account management quality | It is picked as a consolidation move rather than left for one reason | Teams move on once segmentation and flows matter |
| Typical switch | Out to a dedicated SMS vendor, or in from another email tool | Out to Klaviyo or Postscript for SMS | In from Klaviyo or Attentive for SMS | In from a split email and SMS stack | Out to a full retention platform |
Klaviyo
Klaviyo sells a B2C CRM: email, SMS and other channels on top of a customer data platform, with reviews, a helpdesk and AI agents available on the same account. The Shopify app syncs store data, tags, catalog and coupons, and the paid email tier adds predictive analytics, send time optimization and reputation repair AI for deliverability. There is a free plan with a cap on profiles and monthly emails.
The friction is billing. Klaviyo prices email by contacts, not by messages sent, so lists that grow faster than revenue get expensive and brands start pruning. Deliverability warnings during migration are a known pain point, and getting help has been a reason to look elsewhere. Klaviyo has also stopped accepting prescription pharmaceutical sellers, so check acceptable use before you plan a migration. 12th Tribe runs Klaviyo on its storefront.
Attentive
Attentive is built around SMS and extends into email, RCS and push, with AI tools for creating campaigns. Every plan includes onboarding, deliverability help, a dedicated support team, 24/5 service and built-in TCPA compliance tooling. The App Store listing is free to install with a minimum 30-day trial, then month-to-month or long-term agreements.
Pricing is modular and quoted, built on messages, list size, channels and premium AI features, and no amounts are published. That is where exits start: an opening deal that looks different at renewal volume. Brands that bought Attentive for SMS alone have also been cool on the push into other channels and AI journeys when reporting does not make it clear which journeys and messages performed. 7th Avenue runs Attentive on its storefront.
Postscript
Postscript is an SMS-first retention platform for Shopify, with RCS, email and an AI plan bundle. Pricing is public: Starter is free to install with a monthly minimum spend, Growth and Professional are monthly tiers, Enterprise is a custom quote, and messages are billed per SMS or MMS plus carrier fees. Per-message rates fall as you move up tiers. Billing is pay after sending, with no prepaid balances, expiring credits, overages or auto-upgrades, which makes month-to-month cost easy to model.
Competitive rates are a reason brands move SMS here from a bundled platform. Two cautions. A program that fires once a month will not justify any SMS vendor. And account management quality varies, so ask who your CSM is before signing Professional, which is the tier that includes a dedicated one.
Alen runs Postscript SMS Marketing on its storefront.
Listrak
Listrak is a cross-channel marketing automation platform: email, SMS, push, web and onsite experiences driven by one customer profile built through identity resolution. It adds journey orchestration for welcome, cart and browse abandonment, replenishment and post-purchase, plus AI recommendations, predictive segmentation and send time optimization. It is a certified Shopify Plus Partner and connects to Adobe Commerce, BigCommerce, Salesforce Commerce Cloud, loyalty programs, CDPs and CRMs.
The Shopify app is free to install, with external charges billed by Listrak rather than on your Shopify invoice, so you need a quote before you can compare cost against anything else here. Support is 24/7 by phone with weekday live chat. This is the option for a team that wants one vendor and one profile across channels instead of an email tool plus an SMS tool.
Mailchimp
Mailchimp syncs Shopify customers, products and orders for automated emails, SMS, retargeting and win back flows. The ladder runs Free, Essentials, Standard and Premium, priced by contacts, with overages when contact or send limits are exceeded. SMS is an add-on starting at Essentials. Automation counts are capped by tier: up to four on Essentials, up to 200 on Standard. Advanced segmentation, multivariate testing and phone support sit on Premium. Integrations reach beyond Shopify, into Square, Wix, Salesforce, WordPress and the ad platforms.
Brands move to a retention platform when flows and segmentation become the job. Alexandra's Boutique runs Mailchimp Email SMS Marketing on its storefront.
How to decide
Questions people ask
Is Klaviyo or Postscript better for SMS on Shopify?
Postscript is SMS-first and publishes its per-message rates, monthly tiers and carrier fee structure, with no prepaid balances or overages. Klaviyo sells SMS credits alongside email in one account, on a monthly tier that includes a set number of SMS and MMS credits plus carrier fees. If SMS is a major channel and you want cost per send to be predictable, Postscript is the cleaner fit. If you want one segmentation layer across both channels, keep SMS in Klaviyo.
Why do brands leave Attentive?
Cost at scale is one reason. Attentive pricing is modular and quoted on messages, list size, channels and AI features, so the number moves as volume grows. The other reason is focus: brands that bought it for SMS can be unenthusiastic about added channels and AI journeys, especially when reporting does not clearly show which journeys and messages performed.
Can I run email in Mailchimp and SMS in Postscript?
Yes. Both have Shopify apps that sync store data, and Postscript sells SMS without requiring you to move email. The tradeoff is that your segments live in two places, so audience definitions have to be maintained twice. If that duplication becomes a problem, consolidating into Klaviyo or Listrak is the usual next step.
