What is a back-in-stock notification?
A back-in-stock notification app automatically emails or LINE-messages the customers who registered their interest as soon as a sold-out product is restocked. In ecommerce it is precisely the popular products that run out, and customers who find an empty product page usually buy from another store instead, so back-in-stock notifications are an important way to stop losing those sales. The number of registrations is also valuable data in its own right: it shows how much demand exists for each product, which helps you make better purchasing and merchandising decisions.
If you want to grow sales on Shopify, reducing the revenue you lose to stockouts is one of the highest-leverage things you can do. Because so many customers drop off the moment a popular product sells out, an app that adds back-in-stock notifications is close to essential. This article compares seven back-in-stock notification apps available for Shopify and explains what actually matters when you choose one: features, pricing, Japanese-language support and LINE integration.
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StoreCRM feature: back-in-stock notification emails
Back-in-stock emails are opened 65% of the time
According to research by Barilliance, back-in-stock emails average a 65% open rate and a 24% click rate — roughly three times the performance of a typical promotional email. Send to 100 people and around 65 of them open the message, while about 24 click through to the product page. Because the customer asked for exactly this information about a product they already wanted, it is one of the easiest emails to get opened and one of the most productive you can send.
Why back-in-stock notifications can lift sales by up to 15%
A report from Smaily finds that ecommerce stores that introduced back-in-stock notifications saw sales increase by 5–15% on average. For a store doing ¥1 million a month, simply adding the notification is worth an extra ¥50,000–150,000 in monthly revenue. Without it, customers who leave because of a stockout rarely come back — they move on to another store. With it, you can automatically bring those customers back and turn a lost opportunity into a sale. Many brands have recovered significant revenue this way and report returns of several hundred percent on the investment.
The benefits of adding back-in-stock notifications to a Shopify store
The single biggest benefit is that you stop losing sales to stockouts. A customer who finds the product they want but no stock will simply leave; if you can notify them automatically when it arrives, you keep the customers with the highest purchase intent.
An app that reports on registrations, open rates and purchase rates also lets you see which products are in demand and how well your notifications perform, so you can improve the copy and the timing. Because it grows sales without any additional ad spend, it is one of the most cost-effective tactics available, and a great many stores rely on it.
Back-in-stock notifications win back repeat customers and lift revenue at the same time, which makes them a genuinely important part of running a Shopify store.
The impact of back-in-stock notifications
A bar chart comparing each figure on the same scale
Open rate of back-in-stock emails
65%
Click rate of back-in-stock emails
24%
Average sales lift among stores that use them
15%
Sources: "2023 Email Marketing ROI Statistics: Open Rate to Revenue" and "Back-in-Stock Notification Emails: Happy Customers, Thriving Business"
Timing is everything: why the hours after a restock decide your revenue
How long you wait between receiving stock and sending the notification has a large effect on sales. In fact, send timing is one of the biggest factors in how much revenue the notification produces. A customer's "I want this" fades with time, so the sooner the message goes out after the restock, the higher the purchase rate tends to be. If your stock tends to land late at night or early in the morning, it is also worth shifting delivery to a time when customers actually read their email. In short, choose an app that lets you fine-tune when the message is sent and the notification is far more likely to translate into sales. Pay close attention to how flexible the scheduling options are.
The numbers matter: pick an app that tracks everything from signups to purchase rate
Choose an app that reports not only how many people registered but also open rate, click rate and purchase rate. With that data in hand it becomes obvious which products are in demand, whether your send timing is right, and whether the subject line and email content need work. With an app that shows you nothing, you cannot measure anything, and you will never know how much the notifications actually contribute to revenue — which is a real loss, however good the app is otherwise. When you can see the numbers, the improvements to make are clear and the notifications are much easier to turn into sales.
Seven Shopify back-in-stock apps
The right back-in-stock app for your Shopify store depends entirely on what you want to prioritise. In short, the best fit for stores selling in Japan is StoreCRM. Alongside back-in-stock notifications it brings LINE, email and CRM into one place, with full support in Japanese. You can also schedule how long after the restock the message goes out, and it includes detailed post-send reporting.
Price, features, Japanese-language support and depth of analytics all pull in different directions, so the best app varies with your priorities. Choosing one that matches your goals and the size of your store is what makes the difference.
Key: ◎ = strong / ◯ = supported / △ = limited or needs another app / × = not supported
| App | Free plan | Japanese admin / support | Back in stock | Scheduled send after restock | Full CRM | Send history | Conversion rate (CVR) | LINE | Strengths | Key features |
|---|---|---|---|---|---|---|---|---|---|---|
| StoreCRM | ◯ (30-day trial) | ◎ (fully Japanese) | ◎ | ◎ (scheduling available) | ◎ | ◎ | ◎ | ◎ (built-in LINE integration) | Built for the Japanese market; LINE and CRM in one place | Back-in-stock and price-drop alerts, LINE/email, birthday messages, segments |
| AMP Back in Stock | PreOrder | ◎ | △ (partly Japanese) | ◎ | △ | × | ◯ | △ | × | Strong on back-in-stock at a low price | Back in stock, pre-orders, email notifications |
| PreOrder Globo | Back in Stock | ◎ | △ | ◎ | × | × | ◯ | × | × | Flexible pre-orders and restock alerts | Pre-orders, back in stock, product badges |
| Stoq: Back In Stock, PreOrder | ◎ | × | ◎ | × | × | ◯ | △ | × | Simple and inexpensive | Back in stock, pre-orders, analytics |
| Back In Stock (Japanese edition) | ◎ | ◎ | ◎ | × | × | ◯ | △ | △ (possible with a companion app) | Focused on back-in-stock for stores in Japan | Back-in-stock notifications, Japanese UI, LINE notifications |
| Klaviyo | ◎ | × | ◎ | ◎ | ◎ | ◎ | ◎ | △ | Best-in-class automation and analytics | Email/SMS, back in stock, segmentation |
| Omnisend | ◎ | × | ◎ | ◎ | ◎ | ◎ | ◎ | × | Email and SMS in one tool | Email/SMS, automation, back in stock, A/B testing |
StoreCRM
The strongest CRM for Shopify stores in Japan, with back-in-stock, LINE and email in one place
StoreCRM is a full CRM and marketing automation app that includes back-in-stock notifications. Adding the notify-me button, sending the email or LINE message, scheduling when it goes out, and reporting on signups and conversion rate are all handled in a single app. On a sold-out product page the customer registers with an email address or LINE, and is notified automatically the moment the product is restocked. The button can be added without any additional app, though some Shopify themes need minor adjustment. Send times are fully configurable. Because you can export reports on registrations, open rate, click rate and revenue, and send segmented campaigns, StoreCRM also covers the follow-up after the restock: alongside back-in-stock alerts you can send birthday messages and segmented email or LINE campaigns to the same audience and turn them into repeat customers. It is fully localised into Japanese with local support, and it gives you everything you need to turn a stockout into a sales opportunity.
AMP Back in Stock | PreOrder
Keep selling while you are out of stock, with strong back-in-stock and pre-order support
AMP Back in Stock | PreOrder is a non-Japanese Shopify app with a strong feature set for back-in-stock alerts and pre-orders. You can add a notify-me button or a pre-order button to sold-out items, and once a customer registers, the app reaches them immediately by email, SMS or browser push (which requires the customer's permission) as soon as the product arrives. It also includes analytics that show how much demand each product has, which helps with inventory planning and with deciding when to restock. It runs comfortably across large numbers of SKUs, so it suits growing stores and catalogues with a lot of products. Button styling can be matched to your brand and multiple languages are supported, so the path from restock to notification to purchase can be set up in a single click. There is no stated Japanese UI or local support, so check theme compatibility and translation before you commit.
PreOrder Globo | Back in Stock
PreOrder Globo, strong on both restock alerts and pre-orders
PreOrder Globo | Back in Stock is a Shopify app for recovering the sales you would otherwise lose while out of stock. You can place a "Notify Me" button on the product page and the app emails customers automatically when the item is back. It also supports pre-orders, so you can take orders before stock arrives and secure the sale in advance. Sold out stops meaning "no longer available" and starts meaning "the next chance to sell". Multi-language support, broad theme compatibility and customisable notification templates make it a good fit for international stores and large catalogues. Purely in terms of Japanese support and a Japanese-optimised UI it falls behind apps built for the domestic market, so if you sell in Japan, check the theme and the rendered output before rolling it out.
Stoq: Back In Stock, PreOrder
Back in stock and pre-orders on a budget, with notifications you can write in Japanese
Stoq: Back In Stock, PreOrder is a good-value app that covers back-in-stock notifications and pre-orders together. Add a notify-me button to the product page and the app sends email or SMS automatically when stock arrives. Because you can also take orders before the restock, you capture as much demand as possible.
The Stoq admin is in English, but the button label and the notification emails can be customised in Japanese. The settings are simple and easy to work with, which makes it a good choice for stores that want back-in-stock notifications at a low cost. Compared with PreOrder Globo it is less flexible, but noticeably easier to run day to day. If you want both back-in-stock notifications and pre-orders, this is the app to look at.
Back In Stock (Japanese edition)
A Japanese admin and LINE notifications, turning sellouts into opportunities
Back In Stock (Japanese edition) is a Japanese-language app that emails customers automatically when a sold-out product is restocked, and can send LINE notifications when combined with another app. LINE delivery is configured using an integration app or Shopify Flow. Because you can see how many customers asked to be told about each sold-out item, it also makes demand visible. Adding the button and customising the notification copy are both no-code. It also includes a low-stock alert that warns the store when inventory falls below a threshold, so you can act before you lose sales. That is separate from a pre-order feature — no payment is taken. Its main strength is that everything, including the admin, is in Japanese and easy to follow, which suits stores operating in Japan. Plans start at $9.50 a month (around ¥1,500), so smaller stores can adopt it easily, and there is a free plan (up to five notifications) to try it out. It is a strong option if you sell in Japan and want to start with back-in-stock notifications at low cost.
Klaviyo: Email Marketing & SMS
A serious international CRM for growing on Shopify, covering email, SMS and back-in-stock alerts
Klaviyo: Email Marketing & SMS is an email and SMS marketing app for Shopify that works from real-time store data and covers everything from the purchase experience through to nurturing repeat customers. It handles post-purchase follow-up, automation flows, back-in-stock notifications and AI-assisted segmentation, so you can be precise about what you send, when, and to whom. Its advantage over the other apps here is that it is not a dedicated back-in-stock tool: where Stoq or the Japanese edition of Back In Stock cover the simple "sold out to restocked" path, Klaviyo works as a full CRM spanning email, SMS, push notifications, and purchase-data analysis. Push requires Klaviyo Mobile Push, a separate app. Back-in-stock automation is supported as well. Setup cost and complexity are on the high side, but it is an excellent fit for stores in a growth phase or any team that wants to work from data. Note that the admin and support are in English only.
Omnisend Email Marketing & SMS
Easier to get started with than Klaviyo, with a broad feature set
Omnisend Email Marketing & SMS is a marketing automation app for Shopify that manages email, SMS and push notifications together. A large library of email templates, popups and ready-made automation flows such as abandoned cart can be enabled in one click, and back-in-stock notifications and follow-up campaigns are straightforward to configure. Back-in-stock automation is supported. Its segmentation, based on purchase history and email behaviour, is accurate and makes campaigns easy to optimise. Compared with Klaviyo, which is stronger on advanced analysis and finely built segments, Omnisend is cheaper and less complex to configure, while still covering multiple channels behind a clear UI — which is why growing stores find it manageable. It is not limited the way a dedicated back-in-stock app is, and combining email and SMS gives you more dimensions to work with, so it tends to show up quickly in revenue. The admin and support are in English, but it is simple enough to operate that many Shopify stores choose it.
Summary
Of all the back-in-stock apps, StoreCRM is the one to look at first. It is a CRM built for the Japanese market that handles not just the notification but conversion analytics, LINE integration and segmented campaigns in one place, and it is particularly strong on the follow-up after the notification goes out.
There are also apps like AMP Back in Stock that simply do back-in-stock notifications well, and multi-purpose options like Stoq and PreOrder Globo that combine restock alerts, pre-orders and low-stock warnings.
Beyond those, Klaviyo and Omnisend offer advanced analytics on top of an English UI, while the Japanese edition of Back In Stock gives you a Japanese interface and local support.
Which one is right depends on the size of your store, how your team works, and how much functionality you actually need. Decide first whether you are optimising for simplicity, breadth of features, CRM depth or Japanese-language support, and choose the app that matches the stage your store is at.
