Guide
Back-in-stock notifications for Shopify: the complete guide.
Back-in-stock notifications tell shoppers when a product they wanted is available again. On Shopify, you have three options: manual outreach, Shopify's built-in stock notification email, and dedicated back-in-stock apps. Industry recovery rate is 8 to 12 percent, which makes back-in-stock alerts one of the highest-ROI emails an ecommerce store can send.
What back-in-stock notifications are
A back-in-stock notification is a message — usually email or SMS — that tells a shopper a product they were interested in is available again. The shopper opts in by entering their email or phone number on a sold-out product page. The store sends the alert the moment that product or variant is restocked. The flow has three steps: capture the signup, watch the inventory, send the alert. Done well, it recovers revenue you would otherwise lose to competitors.
Why back-in-stock notifications matter
Stockouts are not neutral events. A shopper who sees "out of stock" and leaves usually does not return on their own.
8 to 12%
Typical recovery rate when alerts are sent within 24 hours of restock. (Industry benchmark across email and SMS.)
70%+
Open rate on back-in-stock emails — among the highest of any transactional email type, because shoppers explicitly asked for them.
$0.40 to $1.20
Revenue per signup, depending on average order value and recovery rate.
The math on a typical store
Take a Shopify store doing 50 distinct stockouts a month, with 20 interested customers per stockout and a $80 average order value. At a 10% recovery rate, that is 100 recovered orders × $80 = $8,000 in monthly revenue that would otherwise leave for a competitor.
Three ways to do back-in-stock on Shopify
There are three reasonable approaches. Pick based on volume, budget, and how much control you want over branding and deliverability.
1. Manual outreach
Track interested customers in a spreadsheet. Email them yourself when products restock. Free, but does not scale beyond a handful of stockouts per month and lacks attribution.
Use if: under 5 stockouts a month and you want zero apps.
2. Shopify's built-in stock notification email
Shopify offers a basic notification feature in some themes. It sends a generic email when stock is replenished. Free, but no SMS, no on-site widget, no per-alert revenue attribution, and limited template control.
Use if: low volume and you want zero third-party tools.
3. A dedicated back-in-stock app
Apps like Slingshot collect signups via an embedded widget, send email and SMS automatically, and report which alert earned which sale. Costs $0 to $59 per month depending on volume.
Use if: 10+ stockouts a month or you care about attribution.
Step-by-step: setting up back-in-stock alerts with a dedicated app
Using Slingshot as the example because the workflow is identical for most dedicated apps. Total time: about 5 minutes.
- 1
Install from the Shopify App Store
Search for the back-in-stock app in the Shopify App Store. Click Install. Approve the permissions request. The app syncs your products and inventory automatically.
- 2
Pick an email template and match your brand
Most apps ship with several pre-built templates. Pick one. Set your logo, brand colors, and a default subject line. Add an optional discount code if you offer one.
- 3
Customize the on-site signup widget
The widget appears on sold-out product pages. Set its position, copy, and styling to match your store. Most apps let you do this without touching code.
- 4
Optional: enable SMS
If your customers are mostly US or Canada based, enable SMS alerts. SMS opt-in approval is required by TCPA — most apps handle this for you. Pricing is usually pay-as-you-go around $0.015 per message.
- 5
Test the flow
Pick a product, set its inventory to zero, sign up for an alert from a test email. Restock the product. Confirm you get the email. This catches template errors before real customers see them.
Deliverability and compliance
An alert that lands in spam earns nothing. The fundamentals matter.
Use a custom-from domain with DKIM
Sending from yourdomain.com instead of a shared app domain meaningfully improves inbox placement. Most pro-tier apps include this; it requires a DNS record.
Auto-inject business address
CAN-SPAM (US), CASL (Canada), and GDPR (EU) all require a physical address in marketing emails. Good apps inject this automatically — verify yours does.
Honor opt-outs immediately
An unsubscribe link is mandatory and must process within 10 business days under CAN-SPAM. Standard apps handle this.
TCPA opt-in for SMS
SMS in the US and Canada requires explicit opt-in with clear language about what the shopper is signing up for. Apps like Slingshot handle the consent flow.
Metrics that matter
Most apps report sends, opens, and clicks. Those tell you the alert was delivered and read. The metrics that tell you it earned revenue:
Recovery rate
Percentage of alerted shoppers who buy within 7 days of receiving the alert. Industry benchmark is 8 to 12 percent. Below that, your alerts may be slow or off-brand.
Revenue per alert
Total revenue attributed to the alert divided by alerts sent. Lets you compare templates, channels, and audiences honestly.
Time to alert
Minutes between restock and alert send. Fast wins. If a competitor restocks the same product the same day and alerts faster, they get the sale.
Channel mix
Recovery rate broken down by email vs SMS. SMS often shows higher recovery on time-sensitive products; email wins on considered purchases.
Frequently asked questions
Set up back-in-stock alerts in five minutes.
Free up to 100 alerts a month. No credit card required.
Install Free on Shopify