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Shopify Back in Stock Notifications: Your Options and How to Set Them Up

Shopify doesn’t send back in stock emails on its own. Compare apps, a Shopify Flow route and a manual list, then set up variant-level alerts with clear consent, expiry and reporting.

By ShopOpsy

Published 16 min read

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Shopify has no built-in back in stock notification. Its customer notifications cover orders, shipping and accounts, and the automation templates in Shopify Messaging don't include a restock alert. To add a "Notify me when available" form that emails shoppers when a sold-out variant returns, install an app from the Shopify App Store's Stock alerts category or use the back in stock feature of an email platform you already use. Without an app, Shopify Flow's Product variant back in stock trigger can spot the restock and tell you, but Shopify doesn't document a fully automatic way to email each waiting shopper. You usually send the email yourself: as a Shopify Messaging campaign to a tagged segment, or by hand from a list you keep.

Whichever route you take, record the exact variant, collect clear consent, send only when the stock can be bought online, and delete old requests. This guide follows Shopify's Help Center and developer documentation as checked on 26 October 2026. Admin labels change often, so expect small differences in your store. It is general information, not legal advice.

Does Shopify have a built-in back in stock alert?

No. Here is what each native tool can and can't do:

  • Customer notifications. Shopify's store notifications page describes customer emails for orders, shipping and account events. The customer notifications in Settings > Notifications > Customer notifications are sent for events such as order confirmation, shipping confirmation and delivery. Neither page lists one triggered by a restock. Our guide to Shopify notifications covers the ones you do get.
  • Shopify Messaging automations. Shopify's email and SMS app offers automation templates for abandoned browse, cart and checkout, welcome series, post-purchase and customer appreciation, under Apps > Messaging > Automations. There is no back in stock template, and for custom automations Shopify points you to Shopify Flow. Since 24 March 2026, automations that use Shopify Messaging emails live in the Messaging app rather than under Marketing.
  • Shopify Flow. Flow is a free app on the Basic, Grow, Advanced and Plus plans. Since August 2023 it has had a Product variant back in stock trigger that fires when a variant's inventory rises from 0 or less to 1 or more. But Flow's Send internal email action takes fixed recipient addresses, not a variable, and Shopify describes it as best for emailing staff.

So Flow can tell you that a variant is back, but its Send internal email action can't email each shopper who asked. Shopify Messaging does add a Send marketing email action to Flow, but Shopify doesn't document using it for a list of waiting shoppers (see the Flow section below). In practice, a native setup is a do-it-yourself mix of Flow, a form and an email you send.

Which back in stock option should you choose?

ApproachWhat you set upRecords the variantSends automaticallySuits
Back in stock appAn app from the App Store's Stock alerts category, placed with an app block or app embedUsually; check before installingYesMost stores, especially with many variants
Your email platform's restock featureThe platform's Shopify integration and signup formVariesYesStores already sending email from that platform
Flow, tags and Shopify MessagingA theme signup form, a Flow workflow and one campaign per restockYes, if each tag names a variantPartly: Flow alerts you, you send the campaignSmall catalogs with occasional restocks
Contact form and a manual listYour theme's contact form and a spreadsheetOnly what the shopper typesNoA handful of requests a month

An app may add a monthly fee, but it sends the alerts for you. The two no-app routes need no extra app (Shopify Messaging includes a free monthly email allowance), but someone has to send every restock email, and the Flow route adds every signup to your marketing list.

If the item has a confirmed arrival date and you'd rather take payment now, a preorder may fit better than an alert; our preorder setup checklist walks through that decision. For what shoppers see on a sold-out product in the first place, see our guide to Shopify out of stock settings.

What does a good notify-me flow need?

Use these as your requirements, whichever route you choose.

Signups at variant level

A shopper who wants size M in blue shouldn't hear about size XL. The form should appear only when the selected variant is sold out, update when the shopper switches options, and store the variant, not just the product. In Liquid, each variant has its own id and available properties, and its url adds ?variant= to the product link, so the alert can open the page with the right option already selected.

A variant only sells out when its stock is tracked and Continue selling when out of stock is off. Shopify defines an item as out of stock when inventory is tracked and at zero or below. With overselling on, the shopper can simply buy, so no signup form should show.

Say exactly what the shopper will get, such as one email when this option is back. If you also want to add them to your newsletter, ask with a separate checkbox that starts unticked. Collect only what you need: usually an email address or phone number, and the variant. Text messages need their own consent, and Shopify keeps SMS subscription status separately from email in its customer data.

Sending when stock can really be bought

Send when the variant is available online, not just when a number goes up somewhere. Shopify's multi-location inventory guide says stock at locations that don't fulfill online orders counts in your total inventory but not in the online quantity shoppers see. Shopify's Flow trigger pages don't say which of the two the back in stock trigger watches, so if you hold retail-only stock, test before you rely on it.

Limiting sends to the stock you have

If 200 people wait for 5 units, emailing everyone at once sells the batch out in minutes and disappoints 195 people. Better options:

  • Send in waves, oldest request first, sized to the units that came back, and recheck stock before each wave.
  • Set a minimum quantity before alerting, so one returned unit doesn't trigger 200 emails.
  • Say quantities are limited only when they are.

Expiring and deleting requests

A request from last spring is stale data. The UK ICO's guidance on the storage limitation principle says personal data should be kept no longer than you need it, with retention periods you can justify. Delete each request once its alert is sent, set an expiry for the rest, and tell shoppers how long you keep them.

How to set up back in stock alerts with an app

  1. Choose the products. Leave out discontinued items and anything you will sell as a preorder.
  2. Check inventory settings on each variant: tracking on, Continue selling when out of stock off, and stock at a location that fulfills online orders.
  3. Pick an app from the Stock alerts category. Before installing, check that it records variants, works with your theme, lets you edit the consent wording, supports double opt-in where you need it, can send in waves or above a stock threshold, expires requests, deletes data on request, and reports signups, sends and orders.
  4. Place the signup form. In your Shopify admin, go to Online Store, click Edit theme, open a product template, click Add block and choose the app's block from the Apps section, or turn on its embed under App embeds. Click Save. Shopify's guide to extending your theme with apps notes that app blocks need a compatible theme, while app embeds work with any theme version.
  5. Write the messages: the form text, the confirmation and the alert itself. The alert should name the variant, show its image and price, link straight to it, and include your business name and an unsubscribe link.
  6. Update your privacy policy to mention restock alerts and the app that stores them. Our Shopify privacy policy guide explains what it should cover.
  7. Test end to end. Sign up for a sold-out variant with your own email, raise its stock from 0, check that the alert arrives and opens the right option, then reset the stock.

ShopOpsy is building NextBatch Preorders, an app for selling preorders in production batches, each with a capacity and a ship-by date, with back-in-stock alerts included; it isn't available to install yet.

How to send alerts with Shopify Flow and Shopify Messaging

This no-app route uses three Shopify tools. It suits stores that restock a few products at a time.

1. Add a variant-aware signup form

Shopify's newsletter form, {% form 'customer' %}, creates a customer record and marks it as accepting marketing email. Dawn's newsletter section sends a hidden contact[tags] field with the value newsletter, and the same field can carry a tag that names the variant. A developer can add a form like this to your product template:

{%- liquid
  assign sold_out_count = 0
  for variant in product.variants
    unless variant.available
      assign sold_out_count = sold_out_count | plus: 1
    endunless
  endfor
-%}
{% if sold_out_count > 0 %}
  {% form 'customer', id: 'restock-signup' %}
    <label for="restock-variant">Option</label>
    <select id="restock-variant" name="contact[tags]">
      {% for variant in product.variants %}
        {% unless variant.available %}
          <option value="restock-{{ variant.id }}">{{ variant.title }}</option>
        {% endunless %}
      {% endfor %}
    </select>
    <label for="restock-email">Email</label>
    <input type="email" id="restock-email" name="contact[email]" required>
    <p>We'll email you when this option is back in stock. Signing up also
    subscribes you to our marketing emails; you can unsubscribe at any time.</p>
    <button type="submit">Notify me</button>
  {% endform %}
{% endif %}

Before you rely on it:

  • Every signup becomes a marketing subscriber, so the text next to the button must say so.
  • Double opt-in makes shoppers confirm by email first. To turn it on, go to Settings > Notifications, click Customer notifications and, in Marketing double opt-in, select Customer marketing confirmation.
  • Existing customers: Shopify's documentation doesn't say whether this form adds tags to a customer who already exists, so test with an email that's already in your customer list.
  • Products without options show "Default Title" in the menu, so relabel it or hide the menu.

2. Build the Flow workflow

In Shopify Flow, create a workflow with these steps:

  1. Trigger: Product variant back in stock.
  2. Get customer data, with an advanced query for the variant's tag, such as tag:'restock-123456789'. The customers query documents the tag filter, and Shopify's Get customer data reference shows a Liquid variable inside an advanced query. Replace the number with the variant's ID: Shopify's Flow variable examples use productVariant.legacyResourceId for a variant's numeric ID, so the query becomes tag:'restock-{{ productVariant.legacyResourceId }}'.
  3. Count the results, then add a condition that the count is greater than 0.
  4. Send internal email to yourself with the product, the variant and the number of people waiting.
  5. Wait long enough to send the campaign, such as two days.
  6. Get customer data again with the same query, because Shopify's Wait action guide says data fetched before a wait isn't available after it. Then use For each with Remove customer tags to clear the restock tag. Shopify documents For each for tagging each customer that Get customer data returns, but its Remove customer tags page only describes the customer who triggered the workflow, so check in a test run that the tags really go. If they don't, select the customers in Customers and use the Remove tags bulk action.

The Get customer data reference also says the action returns up to 100 customers at a time. If more people than that wait for one variant, this route stops being practical. To test the workflow, change a variant's inventory from 0 to 1 or more.

3. Send the campaign

When the internal email arrives, go to Customers > Segments and create a segment with customer_tags CONTAINS 'restock-123456789', using Shopify's segment query syntax. Save it, then click Use segment and Email, as Shopify's guide to managing customer segments describes. You can also start from Apps > Messaging > Create campaign and pick the segment in the To field, as Shopify's campaign guide describes. That guide says stores on the Basic, Grow, Advanced and Plus plans get 10,000 free emails a month, and Shopify's subscriber list guide says Shopify Messaging filters out customers who don't accept email marketing.

Can Flow email the shoppers itself?

Possibly, but Shopify doesn't document it. Shopify's list of apps that work with Flow shows that Shopify Messaging adds a Send marketing email action, which sends to customers subscribed to email marketing. Shopify's Flow troubleshooting guide says the action fails permanently for a customer who doesn't accept marketing, so check subscription status in a condition first.

No Shopify page describes using this action inside For each after Get customer data. If you try it in place of the campaign, test with two or three tagged accounts and confirm that each one gets exactly one email.

How to handle requests by hand with a contact form

For a few requests a month, a list you keep yourself is enough:

  1. Collect requests. On sold-out products, invite shoppers to use your contact form and name the option they want. Theme contact forms accept extra custom fields named like contact[product], and Shopify sends every submission to your store's sender email address, which you change on the Notifications settings page.
  2. Log each one in a spreadsheet: date, email, product, variant and the wording the shopper agreed to.
  3. Get told about restocks. A Flow workflow with the Product variant back in stock trigger and a Send internal email action emails you when stock returns.
  4. Reply one by one. Email each shopper separately, never with everyone's address in the To or Cc line, then delete the row.

Restock alerts use personal data, so treat them like any other marketing list. Our overview of Shopify GDPR compliance covers the wider picture.

  • Say what shoppers are signing up for next to the form, and link your privacy policy.
  • UK. The ICO's email marketing guidance says you can send solicited email marketing, which the person specifically asked for, without consent. You must still identify yourself and give an opt-out in every message. A newsletter they didn't ask for is a separate question.
  • EU. Under the GDPR, withdrawing consent must be as easy as giving it (Article 7(3)), and once someone objects to direct marketing, their data can no longer be used for it (Article 21(3)).
  • US. The FTC's CAN-SPAM guide judges an email by its primary purpose. Its transactional categories are tied to purchases, accounts or relationships the recipient already has, which an alert for an item they haven't bought doesn't clearly match. It's safest to treat alerts as commercial and follow the guide, including an honest sender and subject line, a valid postal address and an opt-out honored within 10 business days.
  • SMS needs its own opt-in and its own rules; check them for each country before adding text alerts.
  • Expire and delete requests on a schedule you can explain.
  • Block bots. Shopify's store preferences turn hCaptcha on by default for contact and newsletter forms; leave Enable hCaptcha on contact and comment forms checked under Online Store > Preferences.

How to measure back in stock alerts

Track a few numbers per variant rather than one store-wide figure:

MetricHow to work it outWhat it tells you
Signups per variantRequests for each variantDemand to weigh when you reorder
Confirmation rateConfirmed signups ÷ signups (with double opt-in)Form friction or bot signups
ReachAlerts sent ÷ signupsLosses to expiry, unsubscribes and bounces
Click rateClicks ÷ alerts deliveredWhether the message and timing work
Alert conversionRecipients who bought the variant within a set window ÷ alerts sentThe alert's real value
Unsubscribes and complaintsOpt-outs ÷ alerts sentConsent or frequency problems

Tag every alert link with UTM parameters, for example utm_medium=email&utm_campaign=back-in-stock. Shopify's marketing performance guide says traffic with utm_campaign parameters is attributed to marketing, and you can review it in Growth > Attribution, which defaults to the last non-direct click model.

Read the numbers with two caveats. Where a cookie banner is active, Shopify collects data only after consent, which lowers session counts and session-based conversion rates; our GA4 conversion tracking checklist helps you tell that apart from broken tracking. And some recipients would have bought anyway, so compare alert buyers with other sales of the same variant after the restock.

Why aren't my Shopify back in stock alerts working?

What you seeLikely causeWhat to check
No notify-me form on a sold-out productApp block not added, app embed off, or the section doesn't support app blocksTheme editor; your theme's documentation
Add to cart still shows at zeroContinue selling when out of stock is on, or tracking is offThe variant's Inventory section
Signups don't say which size or colorThe form records the product, not the variantSwitch to a variant-level form
Flow workflow never runsInventory tracking off, or stock never reached 0The trigger needs Inventory tracked and fires only on a rise from 0 or less
Alert sent, product still sold out onlineStock at a location that doesn't fulfill online orders, or earlier recipients bought itSettings > Locations; send in waves
Many alerts for a single unitOne returned or corrected unit lifted stock from 0 to 1Add a quantity threshold (see below)
Messaging campaign went back to draftThe segment had no subscribers at the scheduled send timeThe tag, and each customer's marketing status
Far fewer emails sent than signupsNon-subscribers filtered out, unconfirmed double opt-ins, suppressed bouncesYour subscriber list in Shopify Messaging
Spam signupshCaptcha turned offOnline Store > Preferences

For a quantity threshold in Flow, Shopify's Product variant inventory quantity changed trigger includes the previous quantity as inventoryQuantityPrior. A condition such as "previous quantity below 5 and current quantity 5 or more" alerts only when a real batch lands. Unlike the back in stock trigger, it runs even when inventory tracking is off, so check that setting in the condition too.

Frequently asked questions

My theme already has a notify-me form. Where do the signups go?

It depends on which Shopify form the theme uses, so check your theme's documentation. A form built on the theme contact form sends each request to your store's sender email address, like any contact message. One built on the newsletter form creates a customer record marked as accepting marketing email, which you'll find under Customers. Either way, Shopify doesn't email the shopper when stock returns; you follow up with Flow or by hand, as described above.

Do back in stock signups become email marketing subscribers?

Only if your form makes them so. Shopify's newsletter form marks every signup as accepting marketing, so the Flow route always adds them to your list. Apps differ: check where the app stores each address and which consent status, if any, it writes to the Shopify customer.

Can I send back in stock alerts by text message?

Yes, if your app or email platform sends SMS, and only to shoppers who opted in to texts. Shopify records SMS marketing consent separately from email consent, so an email opt-in doesn't cover texts.

Should I show when the item will be back?

Only when you have a confirmed date. Otherwise say you'll email when it's back. For a well-known restock, a short note in an announcement bar reaches shoppers before they reach the product page.

Sources

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