Does it feel as though email open rates fall every year and your messages no longer reach customers? SMS marketing, with its 98% open rate, is attracting attention as the answer. But the popular SMS apps for Shopify are mostly built outside Japan, and using them here comes with particular caveats.
This article covers the basics of SMS marketing, the cost and feature barriers you hit using apps from abroad in Japan, and a detailed comparison of the main options — Attentive, Postscript, Klaviyo and Omnisend — so that Shopify merchants in Japan can choose the right app for their business.
Why SMS now? Four benefits, and what to watch out for
SMS is being reappraised as a marketing channel because it has strengths no other channel can match. Here are four points every ecommerce operator should know, covering both the upside and the caveats.
A 98% open rate: near certainty that your customer sees it
The greatest benefit of SMS marketing is its extraordinary open rate. Various studies put it at around 98% — roughly five times the 20% typical of email. Information that only one person in five sees by email reaches almost everybody by SMS.
Being able to put something you absolutely need customers to see — a product launch, an important sale — onto their phone with that confidence is an attraction no other channel offers.
Delivered instantly, read instantly: perfect for flash sales
SMS is not only opened; it is opened fast. Data suggests 90% of recipients open a text within three minutes of receiving it — in contrast to email, which is often read hours or days later.
That immediacy is enormously effective for time-critical information: flash sales that are won or lost in the first few hours, or an urgent announcement about a limited quantity. SMS reaches customers at their most active moment, which makes it a powerful defence against lost sales.
The trump card for abandoned carts
Abandoned carts — customers who add something and never buy — are a shared frustration in ecommerce. Here too SMS is a very effective answer. Most people mean to buy later and simply forget, so reminding them while it is still fresh matters.
Case studies from KDDI Message Cast, KDDI's SMS delivery service, report that sending an SMS reminder to customers who abandoned a cart recovered purchase rates by 10–15%. Where an email reminder is easily missed, a text lands directly on the phone's lock screen, reawakening intent and recovering revenue.
A caveat: the cost and character-count barriers in Japan
For all its benefits, sending SMS within Japan comes with important differences from elsewhere. The first is cost. Domestic SMS over a high-quality route costs roughly ¥8–18 per message. That is expensive compared with email, so sending indiscriminately adds up quickly. The second, and more important, is the character limit.
A text normally holds 160 single-byte alphanumeric characters, but a single Japanese (double-byte) character drops the limit to just 70. Anything over 70 characters counts as two messages and costs twice as much. Even something as short as "[Store name] Sale on now! Here: (URL)" easily exceeds 70 characters in Japanese, doubling the cost without your intending it.
Four leading Shopify SMS apps compared for use in Japan
The popular SMS marketing apps for Shopify are Attentive, Postscript, Klaviyo and Omnisend. All four are best-in-class tools in the global market, particularly in North America — but they are designed around the North American market. That means merchants in Japan run into cost and feature problems that are specific, and sometimes fatal. Here is what each offers, and how well it works here.
Attentive
Attentive is unmatched at growing an SMS subscriber list — but that strength is built for North America. It targets large brands on Shopify Plus, and its greatest weapon is its patented "Two-Tap" technology: tapping a button on a popup launches the phone's messaging app automatically, and pressing send completes the signup.
Removing the need to type a phone number entirely produces a dramatic increase in list growth. Using it in Japan, however, comes with a significant constraint: picture messaging (MMS), one of Attentive's attractions, is not currently available here.
In short, Attentive is a powerful weapon for merchants who want serious results selling into North America, but for domestic use in Japan, losing MMS — its greatest strength — is a real drawback.
Postscript
Postscript positions itself consistently as the SMS specialist built purely for Shopify. Its strengths are automation flows deeply connected to Shopify data, and two-way communication built around conversation with the customer.
Integrated with the helpdesk tool Gorgias, for instance, SMS replies become support tickets and the whole conversation can be handled over SMS. Using it in Japan, though, presents serious problems. As with Attentive, MMS is unavailable, and sending to Japan costs about $0.20 per message against roughly $0.015 within the US — more than ten times as much.
In short, Postscript is ideal for North American merchants who want deep Shopify integration and conversational commerce. For running it in Japan, the sending cost is a major barrier.
Klaviyo
Klaviyo is widely known as a CRM and marketing automation app combining email and SMS, but in the Japanese market its SMS functionality is effectively unusable. Its greatest strength is deep analysis of Shopify customer data — purchase history, on-site behaviour — and automated outreach to fine-grained segments such as "customers who viewed a particular product three times without buying".
The important caveat is that Klaviyo's SMS does not officially support sending to Japan (country code +81) at present, or supports it only in very limited form.
In short, for a business selling within Japan, the realistic use of Klaviyo is as a foundation for email and data analysis. Running its SMS here is not currently a practical option.
Omnisend
Omnisend is popular with small and mid-sized businesses for its balance of features and value, but its SMS needs care in Japan. It manages email, SMS and web push in one approachable platform, and it is cheaper and easier to adopt than Klaviyo.
Using SMS in Japan raises specific problems, though. The most serious is that texts sent to Japanese mobile numbers show an unfamiliar international number as the sender rather than your brand name, which customers may well mistake for a phishing attempt. On top of the 70-character limit for Japanese, the mandatory unsubscribe URL consumes more than 20 characters, so costs rise unintentionally.
In short, Omnisend is attractive for merchants who want a low-cost, capable tool centred on email marketing — but the international sender number alone risks damaging trust with customers in Japan.
Summary
All four of the apps covered here are highly capable in the global market. For a business whose main target is Japan, however, the reality is significant constraints: expensive sending, no picture messaging, and in some cases no ability to send to Japan at all.
To choose well for your business, use these criteria.
- Selling mainly to North America or other markets abroad: marketing built around local commercial practice is essential. Attentive, with its strength in list growth, and Postscript, with its smooth Shopify integration, are the strong candidates.
- Selling mainly within Japan: understand the constraints of apps built abroad. One effective strategy is to use these apps primarily to strengthen email marketing, while turning to a LINE integration app such as StoreCRM — far more familiar to Japanese users — as the alternative to SMS.
