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# How to send back in stock alerts through Klaviyo

STOQ's **Klaviyo app** lets you send **automatic back-in-stock alerts** through your Klaviyo account instead of STOQ's built-in email. When a product is restocked, STOQ triggers a Klaviyo event that fires a flow and emails your waiting customers - giving you full control over email design and delivery through Klaviyo's editor.

This guide walks you through switching to Klaviyo as your email provider, connecting the app, setting up flows for back-in-stock alerts and reminders, and verifying everything works.

### Overview

STOQ can send back-in-stock notifications through three email platforms: **STOQ** (built-in), **Klaviyo**, or **Shopify Flow**. When you choose Klaviyo, STOQ stops sending emails itself and instead sends event data to Klaviyo, which triggers a flow to deliver the email.

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Here is how it works at a high level:

1. A customer signs up for a back-in-stock notification through STOQ's **Notify Me** widget on your product page.
2. You restock the product in Shopify.
3. STOQ detects the inventory change and sends an event to Klaviyo with product and customer data.
4. Klaviyo receives the event, matches it to a flow, and sends the email using your Klaviyo template.

STOQ creates two metrics (event types) in your Klaviyo account for back-in-stock notifications:

| Metric name | Purpose |
| ---- |
| Back in stock alert (STOQ) | Initial restock notification sent when a product comes back in stock |
| Back in stock reminder 1 (STOQ) | Follow-up reminder if the customer hasn't purchased yet |

Each metric triggers a separate Klaviyo flow with its own email template. This lets you customize the initial alert and the reminder email independently.

|| Note: The metric names above apply when you connect using STOQ's Klaviyo app (OAuth). If you previously used a Klaviyo Private API key, the metric names are "Stoq - Back In Stock Alert" and "Stoq - Back In Stock Reminder 1" instead.

### Prerequisites

Before you begin, make sure you have:

* An active **Klaviyo account** with a plan that supports flows
* **Admin access** to the STOQ app in your Shopify store
* A **paid STOQ plan** — Klaviyo as an email provider is not available on the free plan

### Step 1: Switch to Klaviyo as Your Email Provider

To switch from STOQ's built-in email to Klaviyo for back-in-stock alerts:

1. From your Shopify admin, open the **STOQ** app.
2. Go to **Back in stock alerts** from the main menu.
3. Under the **Notifications** tab, click **Customize email** on the automatic notification step.
4. In the email customizer, find the **Send emails through** section.
5. Under **Email platform**, select **Klaviyo**.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_6qvsbo.png)

Once selected, you will see Klaviyo-specific settings below the provider choice. The first step is to connect your Klaviyo account.

### Step 2: Connect STOQ's Klaviyo App

STOQ connects to Klaviyo through an **OAuth app** — a secure connection that gives STOQ permission to create metrics, templates, and flows in your Klaviyo account.

##### How to connect

1. In the Klaviyo provider settings, under **"1. Connect Klaviyo"**, click the **Connect** button.
2. A new tab opens with Klaviyo's authorization screen. Click **Allow** to grant STOQ access.
3. Return to the STOQ tab and **refresh the page** to confirm the connection.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_18zfg84.png)
Once connected, a green checkmark appears next to "Connect Klaviyo."

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_2l4njd.png)

| Tip: You can also connect Klaviyo from Settings > Integrations in the STOQ app. The Klaviyo section there has the same Connect button.

If you see a warning banner saying *"Authorization was declined"*, it means you clicked **Deny** on the Klaviyo screen. Click **Connect** again and make sure to click **Allow**.

### Step 3: Set Up Klaviyo Flows

After connecting, you need to set up the Klaviyo flows that will send your emails. STOQ offers two setup methods: **automatic** and **manual**.

##### Automatic setup (recommended)

Automatic setup lets STOQ create everything for you — metrics, email templates, and flows — with one click.

1. Under **"2. Choose setup method"**, select **Automatic setup**.
2. Click **Continue**.
3. STOQ shows a progress banner as it works through the steps:
    * Creating templates
    * Creating flows
    * Activating flows
4. When finished, a success banner confirms the setup and lists the flows created:
    * **Back in stock alert**
    * **Back in stock reminder**

Both flows are now live in your Klaviyo account. You can view and customize them in Klaviyo under **Flows**.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_1gtgsyf.png)
![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_1ngkhsc.png)
![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_1fro085.png)

##### Manual setup

If you prefer to configure flows yourself in Klaviyo:

1. Under the setup method, select **Manual** and click **Continue**.
2. STOQ displays the metric name for each notification (e.g., "Back in stock alert").
3. In your Klaviyo account, go to **Flows** > **Create Flow** > **Create from scratch**.
4. Set the flow trigger to the metric shown in STOQ. Under **Your Metrics**, find and select **Back in stock alert (STOQ)**.
5. Add an **Email** action to the flow and design your template.
6. Set the flow to **Live**.
7. Back in STOQ, enter the exact flow name and click **Verify** to confirm the connection.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_nnud89.png)

A green checkmark appears next to the metric name once verified.

Repeat this process for the **Back in stock reminder 1 (STOQ)** metric if you want to send reminder emails through Klaviyo as well.

|| Note: The flow name you enter in STOQ must match the flow name in Klaviyo exactly, including capitalization and spacing.


##### Send test events

After setting up flows (automatic or manual), you can send test events to verify your setup:

1. In the Klaviyo provider settings, click **Send test event**.
2. This sends sample product data to Klaviyo so you can preview how events appear in your flow and template editor.
3. Check your Klaviyo account to confirm the event was received and the flow triggered.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_1p9yojz.png)
### Step 4: Verify Your Setup

After setup, verify that each flow is connected and active.

##### In STOQ

1. Go to **Back in stock alerts** > **Notifications** tab.
2. If Klaviyo is properly configured, the **Customize email** button for each notification step shows no warning banners.
3. Inside the email customizer, green checkmarks appear next to both "Connect Klaviyo" and the flow metric name.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_1yj7wy9.png)
##### In Klaviyo

1. Go to **Flows** in your Klaviyo account.
2. Look for the flows STOQ created (e.g., "Back in stock alert (STOQ)").
3. Confirm each flow status is set to **Live** (not Draft or Manual).

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_13stmss.png)
### Step 5: Choose Whether Signups Are Subscribed to Marketing

 In the Klaviyo provider settings, the **Settings** section controls how new signups are added to your Klaviyo audience.
By default, STOQ **subscribes everyone** who signs up through your "Notify me when available" form to marketing in Klaviyo. This is intentional: a standard Klaviyo **marketing** flow only delivers to subscribed profiles, so subscribing the signup guarantees the restock alert actually reaches them.

If you'd rather not subscribe shoppers who didn't opt into marketing, you can switch your STOQ flow to **Transactional** in Klaviyo and turn this setting off — then only customers who genuinely accepted marketing are subscribed.

##### How to configure

1. Go to Back in stock alerts > Customize email and select Klaviyo as the provider (email or SMS template).
2. Scroll to the **Settings** section.
3. Toggle **Auto-subscribe profiles to marketing**:
    * **On (default)** — every signup is subscribed to marketing in Klaviyo, so your marketing flow can deliver the alert.
    * **Off** — STOQ only subscribes customers who explicitly accepted marketing. Use this if your STOQ Klaviyo flow is set to Transactional.
4. Click Save at the top of the template editor.

##### How it works

* **Auto-subscribe on (default):** When a shopper signs up, STOQ subscribes their profile to marketing in Klaviyo. A standard Klaviyo marketing flow then delivers the alert. Without this, a marketing flow would skip profiles that aren't subscribed, and they'd never receive the restock email.
* **Auto-subscribe off:** STOQ stops force-subscribing signups, so only customers who genuinely opted into marketing are subscribed. Pair this with a Transactional Klaviyo flow so the alert is still delivered to everyone — transactional messages don't require a marketing subscription.

##### When to turn it off

Turn it off if you don't want to add shoppers to your marketing audience just because they asked to be notified about a restock — for example, to keep your marketing list limited to genuine opt-ins. This only works if your STOQ Klaviyo flow is set to Transactional; otherwise non-subscribed signups won't receive the alert at all.

|| Note: Marking a Klaviyo flow as Transactional requires Klaviyo's approval and is email-only. SMS always requires explicit marketing consent, so SMS signups are only ever subscribed when the customer opts in.

### Customize Email Templates in Klaviyo

After setup, you can fully customize your back-in-stock email templates in Klaviyo's editor.

1. In Klaviyo, go to **Flows** and open the back-in-stock alert flow.
2. Click the email action to open the template editor.
3. Use Klaviyo's drag-and-drop editor to design the email with your brand colors, images, and layout.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_sk7i44.png)
STOQ sends rich event data — including product details, customer info, links, and shop information — that you can use as template variables in Klaviyo with the syntax `{{ event.product_title }}`.

|| Note: For a complete list of all available email and SMS template variables, see [Customize your Klaviyo back-in-stock notifications with variables.](https://help.stoqapp.com/en/article/customize-your-klaviyo-back-in-stock-notifications-with-variables-x3huxg/)

### Reset or Change Setup

If you need to start over or switch between automatic and manual setup:

1. Go to **Back in stock alerts** > **Customize email** > **Send emails through**.
2. Scroll to the bottom of the Klaviyo settings and click **Reset setup**.
3. This clears the flow verification and setup mode, letting you choose again.

![](https://storage.crisp.chat/users/helpdesk/website/-/f/6/9/b/f69b1402a211d800/image_vrdxw9.png)

To switch back to STOQ's built-in email, select **STOQ** under "Email platform" in the provider settings. Your Klaviyo flows will remain in your Klaviyo account but will no longer receive events from STOQ.

To disconnect the Klaviyo app entirely, go to **Settings** > **Integrations** and click **Disconnect** in the Klaviyo section.

### Known Limitations

There are a few constraints to keep in mind when using Klaviyo for back-in-stock alerts.

* **One email provider at a time.** You cannot send back-in-stock alerts through both STOQ and Klaviyo simultaneously. Selecting Klaviyo disables STOQ's built-in email for those alerts.
* **Klaviyo sending limits apply.** Your emails are subject to Klaviyo's account limits and sending policies. High-volume restocks may encounter Klaviyo API rate limits.
* **Paid STOQ plan required.** Klaviyo as an email provider is only available on paid STOQ plans.
* **Alerts still count toward your STOQ limit.** Each back-in-stock event sent to Klaviyo counts as one notification toward your STOQ plan limit, regardless of which platform delivers the email.
* **Slight delay possible.** There may be a brief delay between a product coming back in stock in Shopify and the notification being triggered in Klaviyo.

### Troubleshooting

Here are common issues and how to resolve them.

| Symptom | Likely Cause | Fix |
| ---- |
| Flow verification fails | Flow name mismatch or flow not active | Ensure the flow name in STOQ matches the Klaviyo flow name exactly (including capitalization). Set the flow to **Live** in Klaviyo. |
| Automatic setup failed | API or permission error | Click **Reset setup** and try again. If it fails repeatedly, try manual setup or contact support. The error banner shows the specific reason. |
| Emails not sending after setup | Flow is in Draft or Manual status | Go to Klaviyo > Flows and set the flow status to **Live**. Also confirm back-in-stock alerts are enabled in STOQ and inventory was actually restocked. |
| "Authorization was declined" banner | Clicked Deny on Klaviyo OAuth screen | Click **Connect** again and click **Allow** on the Klaviyo authorization page. |
| Missing product data in emails | Template variables not added | Add STOQ event variables (e.g., `{{ event.product_title }}`) to your Klaviyo template. See the [variables guide](https://help.stoqapp.com/en/article/customize-your-klaviyo-back-in-stock-notifications-with-variables-x3huxg/). |
| Want to switch back to STOQ email | N/A | Select **STOQ** under "Email platform" in the provider settings. Emails will immediately switch to STOQ's built-in system. |

### FAQs

**Q: What is the difference between automatic and manual setup?**
**A:** Automatic setup lets STOQ create the Klaviyo metrics, email templates, and flows for you in one click. Manual setup requires you to create the flow yourself in Klaviyo, set the trigger to the correct metric name, and verify it in STOQ. Automatic setup is recommended for most merchants.

**Q: Do I need a paid Klaviyo plan to use this?**
**A:** You need a Klaviyo plan that supports flows. Klaviyo's free plan includes flows for a limited number of contacts. Check your Klaviyo plan to confirm flows are available.

**Q: Can I use Klaviyo for back-in-stock alerts and STOQ's built-in email for other notifications?**
**A:** Yes. Email providers are configured per notification type. You can set Klaviyo for back-in-stock alerts and use STOQ's built-in email for preorder confirmations, or vice versa.

**Q: What happens if my Klaviyo flow is paused or in draft?**
**A:** STOQ will still send the event to Klaviyo, but the email will not be delivered. Make sure your flow status is set to **Live** in Klaviyo for emails to go out.

**Q: How do I switch back to STOQ's built-in email system?**
**A:** In the email customizer, change the email platform from "Klaviyo" back to "STOQ." Your emails will immediately be sent through STOQ's built-in system instead.

**Q: Can I use my existing Klaviyo email templates?**
**A:** Yes. If you use manual setup, you can create a flow in Klaviyo and use any existing template. Just make sure to add STOQ's event variables to display product and customer information correctly.

**Q: Is the OAuth app connection required, or can I still use an API key?**
**A:** The OAuth app is recommended for new integrations. If you previously set up a Klaviyo Private API key, it will continue to work. However, the OAuth app provides better security and enables automatic setup.

**Q: Can I track email performance in Klaviyo?**
**A:** Yes. All emails sent through Klaviyo flows appear in your Klaviyo analytics with standard metrics like open rates, click rates, and revenue attribution.