Postscript is the SMS-first marketing platform built specifically for Shopify, and it occupies a position email-led tools like Klaviyo or Omnisend cannot fully match: SMS as the primary channel, not the secondary one. For DTC brands where text drives meaningful revenue, the depth of Postscript’s SMS-specific capabilities is the difference between an SMS programme and a serious revenue line.
What it actually does for ecommerce sellers
Postscript handles SMS and MMS marketing — text campaigns, automated flows, two-way conversations between brand agents and shoppers, and SMS-specific landing pages designed to capture mobile sign-ups. The Shopify integration is exclusive and native: every order, customer, and product event flows in without configuration, and the segmentation engine slices that data with the same surgical precision Klaviyo brings to email.
The features that matter for ecommerce specifically: keyword campaigns (text JOIN to opt in, GIFT for a discount), abandoned-cart SMS that recovers checkouts at much higher rates than email alone, post-purchase flows for upsells and review requests, win-back sequences for lapsed customers, and a conversational layer where customers can reply to texts and reach a human agent. The 2024-2025 platform additions include AI-assisted reply suggestions for the conversational layer, predictive send-time optimisation per recipient, and a Sales Associates feature that lets your in-store or showroom staff text customers personally with full SMS compliance handled in the background.
Compliance is genuinely the unsung strength. SMS regulation in the UK and US is strict (PECR, TCPA, and provider-specific rules), and Postscript’s compliance tooling — sign-up consent capture, automatic opt-out handling, time-of-day restrictions, regulatory templates — keeps shops out of trouble in a way generic SMS APIs do not.
Best for
- Shopify-native DTC brands doing £50,000+ monthly revenue with mobile-skewing customers (fashion, beauty, supplements, lifestyle).
- Shops where SMS is a primary channel rather than an email afterthought — flash sales, limited drops, time-sensitive promotions.
- Brands with high repeat-purchase frequency where post-purchase and win-back SMS flows pay back fast.
- Customer-experience teams who want SMS as a two-way support channel alongside email and chat.
It is not the right answer for shops on platforms other than Shopify (the integration depth is what makes it work), brands without an existing email programme (start with email first; SMS amplifies, it does not replace), or operators in markets with restrictive SMS regulation that Postscript does not cover.
Pricing breakdown
Postscript prices messaging via consumption rather than tier — you pay per message sent based on destination and message type, with a monthly platform fee. For a small-to-mid Shopify shop, expect £100-£300 per month all in for a healthy SMS programme, scaling with subscriber count and send frequency. The platform fee tier system roughly works as: Starter at no platform fee for shops under a usage threshold, Growth in the £75-£200 range for typical mid-market shops, Professional for higher-volume senders with custom pricing.
The right way to size Postscript spend: assume £0.012-£0.025 per SMS in the UK and US (varies by provider routing and message length), multiply by your expected sends per subscriber per month, multiply by subscriber count. Budget conservatively and treat the early months as learning what message frequency keeps unsubscribes low.
Where it falls short
The biggest constraint is Shopify-only. If you are on WooCommerce, Magento, BigCommerce, or a custom platform, Postscript is not an option — you’ll need Attentive, Klaviyo SMS, or Omnisend depending on what fits.
The price model rewards established programmes and punishes experimentation. A shop that wants to test SMS without committing finds that the per-message costs add up before any flows generate meaningful revenue, and the platform fee adds to that. This is structurally fine — SMS is a higher-cost, higher-converting channel — but small operators sometimes pull the plug before a programme matures.
Coverage in international markets is solid for major destinations but inconsistent in emerging markets and some EU corridors. Brands with multi-region programmes should verify deliverability and pricing per market rather than assuming global parity.
Finally, the conversational layer requires staffing. Two-way SMS only works if someone replies in a reasonable timeframe; without a dedicated person or a Sales Associates team, customers send replies into the void and the channel quietly degrades.
Compared to the alternatives
The realistic competitive set: Attentive is the enterprise-tier competitor with a deeper feature set for very large DTC brands, but pricing that puts small shops out of reach. Klaviyo SMS is the natural alternative for shops already running Klaviyo for email — less SMS-native than Postscript but unified data and one bill. Omnisend’s SMS module is the budget option, suitable for shops where SMS is secondary to email rather than a strategic channel. SimpleTexting and EZ Texting exist but lack the Shopify-native depth and ecommerce-specific compliance tooling that Postscript and Attentive provide.
The decision in plain terms: Postscript for SMS-first Shopify shops, Klaviyo SMS for shops already inside the Klaviyo ecosystem, Omnisend SMS for cost-sensitive operators, Attentive for enterprise volume. Most brands settle into one of those four within their first year of running SMS seriously.
Our take
For Shopify DTC brands above £50,000 monthly revenue with the right customer profile, Postscript is the highest-ROI SMS platform on the market — the Shopify-native integration depth, the compliance tooling, and the conversational features genuinely make SMS a strategic channel rather than a campaign-only afterthought. The price is real, the staffing requirement for two-way is real, and the platform lock-in (Shopify-only) is real. For shops that can absorb those constraints, the channel typically generates 8-12% of total revenue once mature, which dwarfs the platform cost. For everyone else, run SMS through Omnisend or Klaviyo and revisit Postscript when the dedicated SMS programme is ready to graduate.
FAQ
Does Postscript work outside Shopify?
No — Postscript is exclusively a Shopify-integrated platform. For WooCommerce, BigCommerce, or other platforms, the equivalent options are Attentive (large brands), Klaviyo SMS (if already using Klaviyo for email), or Omnisend (smaller shops).
How is Postscript different from Klaviyo SMS?
Postscript was built SMS-first and treats it as the primary channel; Klaviyo built SMS as an extension of an email platform. Postscript’s two-way conversational features, Sales Associates programme, and SMS-specific compliance tooling are deeper. Klaviyo’s value is in unified email-plus-SMS data and predictive analytics across both channels. Many brands run both — Klaviyo for email, Postscript for SMS — when SMS is a strategic priority.
Is SMS marketing GDPR-compliant in the UK?
Yes, with the right consent capture and opt-out handling. PECR requires express prior consent for marketing SMS, and Postscript’s sign-up flows, opt-in confirmation, and automatic STOP keyword handling cover the compliance baseline. Brands still need their own privacy notice, consent log, and lawful-basis documentation, but the platform does not stand in the way.