Best Shopify back in stock apps: 10 tools compared (2026)

When a product sells out, the demand does not disappear. Shoppers keep landing on the product page, and without a waitlist, nothing brings them back when the stock does. A back in stock app keeps that demand: the shopper joins a waitlist, and the app sends an alert when the product is available again. Every app in this list sends restock alerts. The differences are where the alert lands, whether you can also take pre-orders, and what each alert costs you.

Our pick for most Shopify stores is Kanal, which sends back in stock alerts on WhatsApp. Customers subscribe with one tap, and the alert arrives with a product photo and a direct buy link the moment you restock. Below we compare Kanal with eight apps built for restock alerts and pre-orders, plus Klaviyo, whose email platform includes back-in-stock emails. Our back in stock alerts page shows how the WhatsApp version works on Shopify, from opt-in placement to the alert itself.

How we compared the 10 apps

We read each app's Shopify App Store listing on September 10, 2026, including the full Pricing section, and compared the same points for all of them: the channels a restock alert can use, whether the app also takes pre-orders, the demand reporting it lists, its integrations, and the price of its free and entry plans. Ratings and review counts are the ones shown on each listing that day. We selected eight apps built for back in stock alerts or pre-orders, all currently available on the App Store, plus Klaviyo, whose listing includes back-in-stock emails. Kanal is our own app and comes first. The other apps are ordered by number of Shopify reviews, with Klaviyo last because it is an email platform rather than a dedicated alert app. Plans and prices change often, so check the listing before you install.

Quick comparison

What to look for in a back in stock app

A restock alert looks simple, but a few details decide how many waiting customers come back to buy.

• The channel. Email is the default. SMS, web push and WhatsApp reach customers on their phone. Pick the channel your customers read, and check how each one is billed.
• Signup friction. A Notify Me form asks for an email or a phone number. A WhatsApp opt-in takes one tap, with no form to fill in and no account to create.
• Variants and locations. Alerts should follow the exact size or color the customer asked for and, if you run several warehouses, the stock of the location that ships it.
• Pre-orders. If restocks take weeks, a pre-order option lets customers pay in full or leave a deposit before the stock lands.
• Demand data. A waitlist is a forecast. Look for a report of how many customers wait for each product, so you know what to reorder first.
• Limits and usage fees. Most plans cap alerts, emails or pre-orders per month, and SMS is billed per message on top. Price a restock of your best seller before you choose a plan.
• Integrations. If Klaviyo or another email tool runs your marketing, check that waitlist signups sync to it.

Back in stock alerts vs pre-orders

Alerts and pre-orders answer the same sold-out page in two ways. A back in stock alert collects a waitlist and messages it when inventory returns. The customer pays at that point, and you promise nothing until the stock is on the shelf. A pre-order sells the product before it arrives, in full or with a deposit. You get the order and the cash earlier, but you commit to a delivery date and have to keep customers informed if it moves.

Alerts fit products that come back regularly. Pre-orders fit launches, made-to-order items and long supplier lead times. Five apps in this list do both (Notify Me!, STOQ, Timesact, PreOrder Globo and Amp), and Swym adds pre-order alerts. Kanal focuses on the alert and on the conversation that follows it on WhatsApp, where a customer can reply with a question before buying.

The 10 best Shopify back in stock apps

#1 Kanal WhatsApp, back in stock alerts on WhatsApp

Kanal sends your back in stock alerts on WhatsApp, the channel your customers open every day. Shoppers subscribe with a single tap: a WhatsApp button on the product page, a QR code, or a message to your WhatsApp number, with no email form or account to create. Kanal monitors your Shopify inventory and, the moment a product is available again, sends an automatic alert with the product photo and a direct buy link. The alert lands in WhatsApp, next to the customer's chats, so customers can buy before the restock runs out. The dashboard shows how many customers are waiting for each out-of-stock product, which helps you decide what to reorder first. Kanal also goes further than the alert. On the official WhatsApp Business API, the same account runs abandoned cart recovery, order and delivery notifications, WhatsApp campaigns and an AI chatbot that answers replies 24/7 in 96+ languages (it comes with the Scale plan), so a customer who asks a product question after a restock alert gets an answer in the same chat. Rated 5/5 on the Shopify App Store, Kanal starts at $89/month (Pro), with Scale at $149/month and a demo on request. The back in stock alerts page shows the setup.

#2 Kbite, restock and price drop alerts on a small budget

Kbite adds a customizable "Notify me when available" button to out-of-stock products and sends automatic back in stock alerts by email and SMS. The same signup can build a price drop waitlist, so customers also hear when a product goes on sale, and the product analytics show which items are most in demand. Subscribers can sync to your customer list for email marketing. The free plan includes unlimited subscribers and 30 emails a month. Paid plans cost $5/month (500 email notifications), $9/month (2,500) and $19/month (5,000), with SMS priced by country from $0.02 in the US. Pre-orders are not part of the listing. Rated 5/5 from 4,106 reviews and Built for Shopify, Kbite is worth a look if you want simple email and SMS alerts at a low monthly cost.

#3 Notify Me!, alerts, pre-orders and wishlists in one app

Notify Me! adds Notify Me, PreOrder or Wishlist buttons to out-of-stock product, home and collection pages, then sends automatic restock alerts by email, SMS and web push. It accepts D2C and B2B pre-orders with discounts, notes and partial payments, shows an "only X left" low stock counter, and includes a guest wishlist that works without logging in. Reports cover customer demand and sales forecasting, and it works with Klaviyo, Mailchimp, Omnisend, PushOwl and PageFly. The free Lite plan includes 10 restock notifications, 5 pre-orders and 50 wishlist actions. Paid plans start at $9.90/month (Kickstart, 500 alerts and 500 pre-orders) and reach $39.90/month (Standard), with unlimited plans available inside the app. Rated 4.9/5 from 3,761 reviews and Built for Shopify, Notify Me! is worth a look if you want alerts, pre-orders and a wishlist without stacking three apps.

#4 STOQ, pre-orders with deposits and automatic restock alerts

STOQ, by Artos Software, puts a Preorder or Notify Me button on out-of-stock products, so each product can either take orders early or build a waitlist. Pre-orders cover presales and backorders with deposits or partial payments, including B2B pre-orders, and back in stock alerts go out automatically by email and SMS when you restock. It syncs your mailing list with Klaviyo, works with Mailchimp and Omnisend, supports multiple locations and markets, and reports on customer demand. The free plan includes 10 pre-orders and 30 emails a month. Paid plans cost $10/month (Lite), $29/month (Pro) and $69/month (Unlimited), with SMS at $0.025 each and a fee per pre-order above the plan limit ($0.25 on Lite, $0.10 on Pro). Support is available by live chat 24/7. Rated 5/5 from 3,678 reviews and Built for Shopify, STOQ is worth a look if you want to keep selling during a stockout instead of only waiting for it.

#5 Timesact, pre-orders and waitlists with flexible pricing

Timesact, listed as Preorder Now Presale Timesact, is a pre-order manager with waitlists and restock alerts built in. A product tag switches on pre-orders, back in stock alerts or a coming soon drop, and the inventory manager turns pre-orders and restock alerts on or off as stock levels change. Customers can pay with deposits, partial or split payments, and you can add automatic discounts, order limits, badges, shipping dates and a countdown timer. Restock alerts go out by email, with SMS on paid plans from $0.02 per message for US numbers. The free plan for new users covers 20 orders a month with unlimited emails and Klaviyo. CORE Flex starts at $5/month, and fixed plans with unlimited orders start at $23/month on Basic Shopify, priced by Shopify plan. Rated 4.9/5 from 2,063 reviews and Built for Shopify, Timesact is worth a look if pre-orders drive your launches.

#6 PreOrder Globo, pre-orders and restock emails on two paid plans

PreOrder Globo, by Globo.io, handles pre-orders first and restock alerts second. You can turn on a pre-order button for out-of-stock products or any product, schedule pre-orders with start and end dates, show a delivery note under the button, and take partial payments or apply automatic discounts. Orders are tagged automatically, for example with "preorder" or a shipping date. For restocks, a Notify Me button collects subscribers and the app emails them automatically when the product is back, with batched sends on paid plans. It connects to Klaviyo, Mailchimp, HubSpot, ActiveCampaign and Omnisend. The free plan covers your first 20 presale orders and first 100 restock emails. Lite costs $9.90/month (100 presales a month, 1,000 restock emails) and PRO $19.90/month (unlimited presales, 5,000 restock emails). Rated 4.9/5 from 1,921 reviews and Built for Shopify, PreOrder Globo is worth a look if you want pre-orders and email alerts at a low fixed price.

#7 Appikon Back in Stock, restock alerts by email and SMS

Appikon Back in Stock, by Appikon Software, does one job: it notifies customers automatically when an out-of-stock product is available again. Shoppers join a waitlist through a signup form, and alerts and back order reminders go out by email and SMS. Forms and notifications are fully customizable and work with all themes, and the reports show customer demand for new and existing products. It works with Klaviyo, Mailchimp, PushOwl, Wiser and Zapier. Pre-orders are not part of the listing. The free plan includes 10 emails a month. Starter costs $19.99/month (300 emails, Klaviyo and Mailchimp integration), Pro $29.99/month (1,000 emails, collection page integration) and Premium $49.99/month (3,000 emails, countdown timer), and messages are billed from $0.05 to $0.40 each depending on their length. Rated 4.7/5 from 1,458 reviews, Appikon is worth a look if you only need restock alerts and demand reports.

#8 Amp Back in Stock, alerts, pre-orders and wishlists since 2011

Amp Back in Stock & Preorder +, by HEL SG PTE LTD, has been on the Shopify App Store since 2011. It replaces the Out of Stock label with branded Notify Me and Preorder buttons, then notifies shoppers by email, SMS and web push when items are back. Pre-orders and pre-sells collect payment before your inventory arrives, and wishlists and low stock badges capture demand earlier. Demand insights show what to restock, when and how much, and the listing positions it for catalogs with many SKUs. The free plan includes 10 notifications a month with unlimited registrations. Starter costs $19/month (500 notifications, unlimited pre-orders), Growth $49/month (2,000 notifications, Klaviyo and Mailchimp integration) and Pro $99/month (unlimited notifications, API access and webhooks), with SMS at $0.015 per notification. Rated 4.9/5 from 939 reviews and Built for Shopify, Amp is worth a look if you run a large catalog and want alerts and pre-orders in one place.

#9 Swym Back in Stock Alerts, restock alerts that feed your other tools

Swym Back in Stock Alerts, by Swym Corporation, adds a Notify me button to out-of-stock products and sends automatic restock alerts and reminders by email and SMS. Its focus is the rest of your stack: out-of-stock subscribers can join your email lists and receive alerts through your email or SMS platform, with integrations including Klaviyo, Omnisend, Mailchimp, Listrak and Postscript, and you can run Facebook and Instagram retargeting ads to shoppers interested in a product. It also supports coming soon alerts, pre-order alerts, batch sending, Shopify Locations and AI-powered in-stock recommendations for out-of-stock products. There is no free plan: Starter costs $19.99/month (up to 1,000 alert requests), Pro $59.99/month (up to 10,000) and Premium $99.99/month (up to 25,000, with multi-location support and a REST API), each with a 30-day free trial. Rated 4.7/5 from 442 reviews, Swym is worth a look if your restock alerts need to run through an existing email tool or ad audience.

#10 Klaviyo, back-in-stock emails inside your email platform

Klaviyo is an email and SMS marketing platform rather than a dedicated alert app, but its Shopify listing includes back-in-stock emails among its campaign types, next to price drop, browse abandonment and win-back emails. If Klaviyo already runs your email, restock alerts can sit with the rest of your flows and use segments built on real-time Shopify data. The platform also covers SMS, WhatsApp, mobile push and pop-ups. Pre-orders are not part of the listing. Email is free up to 250 contacts and SMS up to 150 credits. Paid plans start at $15/month for SMS (up to 1,250 credits) and $20/month for email (251 to 500 contacts), and Klaviyo may bill some charges outside your Shopify invoice. Rated 4.7/5 from 3,288 reviews, Klaviyo is worth a look if you want restock emails managed with your other campaigns. Kanal's Klaviyo integration adds WhatsApp to the same stack (it comes with the Scale plan).

Email, SMS or WhatsApp for restock alerts

The channel matters as much as the app, because an alert only works if the customer sees it before the product sells out again.

Kanal's case for WhatsApp is speed: the alert lands in the messaging app the customer already checks, so they can buy before stock runs out again. Email still has a place for customers who only left an email address, and Kanal's Klaviyo integration keeps email and WhatsApp in step. Our best WhatsApp apps for Shopify and best Shopify SMS apps guides compare the tools behind each channel.

Shopify back in stock app pricing compared (september 2026)

Two patterns stand out. Most plans cap what you can send or sell each month, so a big restock can push you into a higher tier, and SMS is billed per message on top. Kanal works differently: a flat monthly plan from $89 (Scale at $149/month) plus WhatsApp messaging fees, with WhatsApp campaigns and cart recovery on the same plan, so the channel you pay for does more than restock alerts.

Which back in stock app fits your store

Start from two questions: which channel do your customers read, and do you want to sell before the restock? Then give each job to one tool, so nobody receives the same alert twice.

• Your customers are on WhatsApp, or you want the alert to open a conversation. Kanal, with one-tap opt-in, instant alerts with a buy link and a waitlist count per product.
• You only need email and SMS alerts. Kbite (from $5/month) and Appikon (from $19.99/month) are worth a look.
• You want to keep selling during stockouts with deposits or partial payments. STOQ, Timesact and PreOrder Globo are worth a look.
• You want alerts, pre-orders and wishlists in one app. Notify Me! and Amp cover all three.
• Your alerts must feed an email tool, an SMS tool or ad audiences. Swym is worth a look.
• Klaviyo already runs your email. Its back-in-stock emails keep restock alerts next to your other flows, and Kanal adds WhatsApp through its Klaviyo integration.