Notify! Back in Stock Review: The App That Pays Itself With 2 Leads

The problem nobody audits

Look at your store right now. Go to admin and filter products by "out of stock" or variants with no inventory. Chances are you have somewhere between 5 and 30 SKUs in that state at any given moment.

Now go to the frontend, browse as if you were a customer. On those products, the button says "Sold out," "Out of stock," greyed out, unclickable. That's everything Shopify's native theme gives you.

The customer who landed on that product did so for a reason. Saw an ad. A creator showed it. Someone shared the link. Found it in Google. They're in high-intent mode. And they leave without you knowing they were ever there.

Notify! Back in Stock swaps that grey button for a "notify me when it's back" form. When you restock, the app emails everyone who subscribed to that SKU/variant. Customer comes back, buys. You captured a lead you'd already lost.

How it works, concretely

Three flows cover 95% of use:

1. Back in Stock notification (the core)

Replaces the "Sold out" button with a form that captures the visitor's email. When you restock inventory in Shopify, the app detects the change and sends an automatic email to everyone who subscribed for that SKU/variant.

2. Pre-order

Allows the customer to pay before the product is in stock. Useful for launches, drops, products in production. Configurable: pre-order at full price, partial deposit, discount for pre-ordering.

3. Wishlist

"Save for later" button that captures email + product. Not strictly back-in-stock, but uses the same infrastructure.

Installation drops the form directly into your product page without requiring Liquid edits. Works out-of-the-box with most OS 2.0 themes.

Pricing

The Starter plan ($10/month) is where most operations live. 2,000 notifications/month covers a medium-volume Shopify with no issues. If you exceed that, you've got a lot of stock movement already — the upgrade to Pro pays itself.

The math: "pays itself with 2 leads"

This is the rule I apply to evaluate any lead-capture app:

• Starter cost: $10/month
• Typical AOV: $40-80 (depends on niche)
• Net margin on AOV: $15-30
• Typical conversion rate of back-in-stock lead to sale: 30-50% (much higher than generic email because intent is sky-high)

If you capture 5 leads/month and 2 convert to sales, you've already covered the cost two or three times. For a Shopify with even 5 products out of stock per week, hitting 5 leads/month is trivial.

What it does well

Consolidated data from 3,139 reviews + operational experience:

• Setup in 15-20 minutes: install, choose templates, done. No Liquid edits in most themes.
• 24/7 responsive support: the most repeated 5-star review is about support speed. In my experience, responses within 1-3 hours even outside business hours.
• Klaviyo integration: if you already use Klaviyo, you can sync back-in-stock leads as a specific segment there. Useful for more sophisticated campaigns than just the "it's back" email.
• Multi-language: if you sell across multiple countries with different languages, notification templates translate automatically based on visitor locale.
• Works with COD apps: tested with Releasit + EasySell, no conflicts.

Where it hurts

Three things worth knowing before installing:

1. Pre-order has a limitation with site-wide Shopify discounts

If you activate pre-order on a product and have a site-wide discount like "Buy X Get Y" or "10% off site-wide," pre-order products don't get included in that promotion. It's a limitation of Shopify's backend, not the app. If your model depends heavily on site-wide discounts, this can generate abandoned carts.

2. Advanced customization lives at admin level, not code

For small changes (button color, form copy) it's perfect — all in the UI. For bigger changes (moving the form somewhere else, integrating with a very unusual custom theme), you can't touch the app's code, only the theme that calls it.

3. Native analytics are basic

It tells you how many leads it captured and how many opened the email. But real attribution (what % of leads actually bought after) requires manual cross-reference with Shopify analytics. If you want granular data, export the leads and match yourself.

Alternatives worth considering

Back in Stock Restock Alerts (STOQ) — direct competitor, 4.8 stars. More modern UI, similar pricing. Solid second place if for some reason Notify doesn't fit.

Amp Back in Stock — more niche, focus on pre-order. If your main use is pre-order/drops and not back-in-stock notifications, evaluate this one.

Klaviyo native — if you already have Klaviyo, you can build the back-in-stock flow with inventory triggers. More setup work (5-10 hours vs 20 minutes), but centralizes everything in Klaviyo. Only worth it if you're already a Klaviyo power-user.

When YES to install

• Your stock drifts out of sync with reality (CRM sync, slow rotation, demand peaks)
• You have more than 2 SKUs/week out of stock with real traffic
• Your net margin easily covers $10/month with 1-2 recovered sales

When NO

• You sell a single product always in stock (doesn't apply)
• Your model is 100% pre-order with planned drops (Amp Back in Stock is better)
• You already have leads list integrated in Klaviyo with custom flows running (overkill)

Verdict

Frequently asked questions

How does it integrate with Klaviyo?

Go to Notify's Settings, connect your Klaviyo API key, map the leads as a specific list. Each back-in-stock notification generates an event Klaviyo receives and you can use for custom flow triggers (e.g., 3 days after if they haven't bought, send a follow-up with discount).

Does the form work on mobile?

Yes, natively responsive. On Pro plan you can customize the mobile-specific form for more control. On Starter, defaults are decent.

What if I restock and don't want to notify everyone?

There's a panel where you can see the waitlist by product and disable sending manually for a specific SKU. Useful if you restock in small quantities and want to sell to the direct channel first.

Does it work with variants (sizes, colors)?

Yes, the lead gets associated with the specific variant (e.g., "size M, color black"). The email only sends when that exact variant comes back, not any variant of the product.

Is there a real lead cap on Starter?

The cap is on notifications sent, not leads captured. You can have 5,000 leads waiting without paying more. Only when you send the emails against those leads do they count against the 2,000/month on Starter. In practice, you restock few times per month, so it's very hard to exceed.