Back In Stock: Restock Alerts Review (2025): How to Rescue Lost Revenue

🔄 Zuletzt aktualisiert am 2. July 2026

The Silent Revenue Killer: “Sold Out”

You know the scenario: A potential customer clicks on your expensive ad, lands on your product page, and is ready to buy. But then they see the dreaded words: “Sold Out”. What happens? The customer is gone. They go to a competitor or simply forget about your product. You paid for the click, but generated zero revenue.

According to a YouGov survey, 65% of all online shoppers were affected by such stock shortages last year. You are losing real money every day because you aren’t capturing the existing buying intent in this moment of frustration.

What if you could offer a way out instead of a dead end? A button saying: “Notify me when available”? What if you could automatically notify these highly interested customers via email or SMS as soon as your shelves are restocked? That’s exactly what “Back In Stock ‑ STOQ” by Artos Software delivers – one of the leading Shopify apps for back-in-stock notifications and preorders. We tested whether it can rescue your revenue too.

What is “Back In Stock ‑ STOQ” Actually?

STOQ is your automated waiting list. It replaces the frustrating “Sold Out” button with a customizable “Notify Me” widget. Customers sign up, and the app handles the rest: As soon as you update your inventory in Shopify, it automatically sends notifications to all waiting prospects.

It relies on two proven channels, reaching your customers where they respond best:

• Email Notifications: The classic method with high open rates for transactional emails.
• SMS Notifications: For maximum attention and quick purchases directly on mobile.

But the app can do more than just wait. With the preorder function (including backorder and presale), you can sell products and generate revenue before they physically arrive in your warehouse. On request, even with deposits or partial payments. This massively improves your cash flow and secures sales that would otherwise be lost.

The Most Important Features in the E-Commerce Check

We looked at what STOQ performs under the hood and why it is so popular with over 18,000 Shopify merchants.

Preorders with Deposits (Cash Flow Booster)

This is what sets STOQ apart from pure restock apps. You can offer sold-out or not-yet-arrived products as a preorder, backorder, or presale. What’s especially strong: you don’t have to collect the full amount upfront – you can work with deposits or partial payments. That way you lock in customers without scaring them off with the full price, and your cash flow starts running before the goods even arrive.

Smart Restocking Insights (Demand Analysis)

The app delivers not just notifications, but valuable data. The dashboard shows you precisely which sold-out products and variants (e.g., Size M, Color Red) are most in demand. This “demand waiting list” is pure gold for your purchasing planning. You no longer order based on guesswork, but based on real, verified customer interest.

Sync to Klaviyo & Mailchimp

If you already use an email marketing tool, you don’t want customer data sitting in an isolated app. STOQ syncs the collected waiting-list contacts to Klaviyo and Mailchimp. That way your highly interested “Notify Me” sign-ups land directly in your existing marketing stack, ready for you to keep engaging them.

Simple Setup & Customization

Installation is incredibly simple. The “Notify Me” widget can typically be added in just a few minutes, with zero code. You can customize the design of the form and button to match your shop theme so it fits seamlessly and looks professional. The fact that STOQ is multilingual is a real bonus if you serve multiple markets.

Who is “Back In Stock ‑ STOQ” a No-Brainer for?

This app is a highly specialized revenue saver. It’s not a must for every shop, but for certain merchants, it’s pure gold.

This is YOUR tool if…

• … you are a Shopify merchant whose popular products or (very importantly) product variants (e.g., Size M in Black) are regularly sold out.
• … you need not just restock alerts but also a preorder system (including deposits) to improve your cash flow.
• … you have high SKU volumes (e.g., in the fashion or sneaker industry) and need an automated solution instead of manually managing email lists.
• … you want to measure real demand for products and pass your waiting-list contacts on to Klaviyo or Mailchimp.

You should probably skip it if…

• … your products are almost never sold out. This applies, for example, to most digital products, print-on-demand items, or services.
• … you want only simple restock alerts and will never use the preorder features. In that case you may be paying for functionality you don’t need – a pure restock app could be cheaper.

The Pricing Model: What Does Saving Revenue Cost?

STOQ offers a free entry point, ideal for testing risk-free. Note: the free plan is tightly limited (10 preorders + 30 emails per month, notifications carry STOQ branding) – for real operations you’ll need a paid plan early on. All paid plans include a 14-day free trial.

Important cost factors: SMS is billed separately on the paid plans (approx. $0.025 per SMS). Preorders above your quota also cost extra (approx. $0.10–0.25 each). With strong growth, your bill becomes harder to predict – budget with a buffer here.

The ROI is Directly Measurable

That’s the beauty of this app: The ROI isn’t an estimate. STOQ tracks the revenue generated directly from a “Back in Stock” notification or a preorder. You see a crystal-clear number in your dashboard showing how much “lost” revenue the app has recovered for you. With a rating of 5.0/5 from over 3,343 reviews and more than 18,000 stores, the investment seems more than worth it for many merchants.

What We Like (The Strengths) & Where It Falls Short (The Weaknesses)

What We Like (The Strengths)

• ✅ Restock + preorder in one: You cover back-in-stock alerts and preorders (including deposits) with a single app – no tool sprawl.
• ✅ Smart Restocking Insights: The app isn’t just a notification tool, but a planning tool. Knowing which products are most in demand helps you invest your capital in the right reorders.
• ✅ Sync to Klaviyo & Mailchimp: Your waiting-list contacts land directly in your existing email marketing – no data silos.
• ✅ Top rating & “Built for Shopify”: 5.0/5 from over 3,343 reviews, more than 18,000 stores, and the official “Built for Shopify” badge speak for maturity and reliability.
• ✅ Multilingual: Handy if you serve multiple markets – you can display the widget and notifications in the right language.

Where It Falls Short (The Weaknesses)

• ❌ SMS costs extra: While emails are included in the quota, every SMS is billed on top (approx. $0.025/SMS). For large lists, this can add up.
• ❌ Tightly limited free plan: 10 preorders + 30 emails per month and STOQ branding on the notifications. For real operations, a paid plan is unavoidable.
• ❌ Preorder + restock as a bundle: If you only want simple restock alerts, you may end up paying for preorder features you never use.
• ❌ Quota overages cost extra: Preorders above the plan limit are billed on top – with strong growth, the bill is harder to predict.

Conclusion: The Right App for Your Growing Shopify Store?

After our test, it’s clear: “Sold Out” doesn’t have to be a dead end for your revenue. It’s a marketing opportunity, and “Back In Stock ‑ STOQ” is one of the most professional tools on the market to capitalize on it. It turns frustration into anticipation and finally into revenue.

Our Plain-Text Recommendation:

For every Shopify merchant dealing with sold-out items or variants who also wants to offer preorders, STOQ is a strong top recommendation. The combination of restock alerts and preorders is practical, the demand data is valuable, and the ROI is immediately visible in the dashboard. If, on the other hand, you only want simple restock emails and never preorders, check first whether you really need the combined bundle.

FAQ: Quick and Simple Answers