How to Sync STOQ customer data to Omnisend for campaigns and automations

STOQ can automatically sync customer data to Omnisend whenever a visitor signs up for a back-in-stock or preorder alert on your store. Each synced contact is added to your Omnisend account with a tag and a custom source property, so you can segment them and include them in your email and SMS campaigns. This guide walks you through connecting your Omnisend account and enabling the sync.

Before You Begin

Make sure you have the following before you enable the Omnisend integration:

A paid STOQ plan (the Omnisend sync is not available on the free plan)
An Omnisend account with permission to create API keys
STOQ installed and active on your Shopify store

Tip: STOQ sends back-in-stock and preorder notification alerts to your customers separately. The Omnisend sync is for adding customer profiles so you can use them in your own marketing campaigns and automations.

How to Get Your Omnisend API Key

Before you can connect STOQ to Omnisend, you need to generate a Private API key in your Omnisend account.

Log in to your Omnisend account.
Click the profile icon in the bottom-left corner.
Go to Store Settings > Integrations & API.
Click API keys, then click Create API Key.
Give the key a name (for example, "Restock-private-key") so you can identify it later.
Make sure the Contacts permission is selected. STOQ needs this permission to create and update contacts.
Click Create and copy the generated API key.

Note: We recommend naming the key "Restock-private-key" so it is clear that this key is used exclusively by STOQ and has limited access.

How to Connect Omnisend and Enable Customer Sync

Follow these steps to connect your Omnisend account and start syncing customers.

Step 1: Open the Integrations Page

Open the STOQ app in your Shopify admin.
Click Back in stock alerts in the left-hand menu.
Navigate to the Settings section, then scroll to Integrations.
Click Set up on the Omnisend card.

Step 2: Enable the Sync Toggle

Turn on the Sync visitors with Omnisend toggle.
Click Save in the top bar to confirm.

enable-omnisend-sync-toggle

Step 3: Enter Your Omnisend API Key

After enabling the toggle, an Omnisend API key field appears.
Paste the API key you copied from your Omnisend account.
Click Save.

Once saved, a green checkmark and "Your Private API key is configured" message confirm the connection.

enter-omnisend-api-key

Tip: If you need to update your API key later, click the Change link next to the confirmation message to reveal the key field again.

Step 4: Set Your Profile Tag

In the Settings section beneath the toggle, locate the Profile tags field.
Enter a tag value (for example, restock-rocket or back-in-stock-signup).
Click Save.

STOQ adds this tag to every contact it syncs to Omnisend. The default value is restock-rocket.

set-omnisend-profile-tag

Note: The profile tag is shared across all your enabled marketing integrations (Shopify, Klaviyo, Omnisend, Mailchimp). Changing it here updates the tag for every platform.

What STOQ Syncs to Omnisend

STOQ sends detailed contact information to your Omnisend account so you can segment and target your campaigns.

Contact Details

When a customer signs up for an alert, STOQ creates a contact in Omnisend with:

Email address (added as an email identifier, if provided)
Phone number (added as a phone identifier, if provided)
First name and Last name (parsed from the customer name, if provided)
Tag (your profile tag value, default: restock-rocket)
Custom property source (set to your profile tag value)

Email and SMS Channel Status

STOQ sets the subscription status for each channel based on the customer's marketing preference:

Accepts marketing: Both email and SMS channels are set to subscribed.
Does not accept marketing (and your store collects promotion consent): Both channels are set to unsubscribed. The contact is stored in Omnisend but will not receive campaigns.
Does not accept marketing (and your store does not collect promotion consent): Both channels default to subscribed, since STOQ cannot determine the customer's preference without a consent prompt.

Tip: If you collect marketing consent on your signup form, STOQ respects that preference when syncing to Omnisend. Customers who do not opt in are added as unsubscribed contacts.

Known Limitations

There are a few constraints to keep in mind when using the Omnisend sync.

The Omnisend integration requires a paid STOQ plan. Free-plan stores cannot enable it.
STOQ syncs contacts one at a time as they sign up. There is no bulk retroactive sync for customers who signed up before you enabled the integration.
The profile tag field is shared across all marketing integrations. You cannot set a different tag for Omnisend and Shopify independently.
STOQ requires the Contacts permission on the Omnisend API key. If this permission is missing, the sync will fail silently.
The API key must remain valid. If the key is revoked or expires in Omnisend, contacts will stop syncing until you enter a new key.
Contacts who sign up with neither an email nor a phone number (for example, push-only subscribers) are not synced to Omnisend.

Troubleshooting

If contacts are not syncing to Omnisend as expected, check the table below.

Symptom	Likely Cause	Fix
Contacts are not syncing to Omnisend	The sync toggle is not enabled	Go to Back in stock alerts > Settings > Integrations > Omnisend and turn on Sync visitors with Omnisend
Contacts are not syncing to Omnisend	No API key is configured	Enter your Omnisend API key in the Omnisend API key field and click Save
Sync fails with no visible error	The API key does not have the Contacts permission	Generate a new API key in Omnisend with the Contacts permission selected
Sync fails with no visible error	The API key has been revoked or expired	Generate a new key in Omnisend and update it in the STOQ integration settings
Contact appears in Omnisend as "unsubscribed"	The customer did not opt in to marketing and your store collects consent	This is expected. STOQ sets unsubscribed status for customers who decline marketing when consent collection is enabled
API key field does not appear	The sync toggle is off or the store is on the free plan	Turn on the toggle first. If you are on the free plan, upgrade under Plans in the left-hand menu
Profile tag is not applied to synced contacts	The profile tag field was empty when the contact was synced	Enter a tag value and click Save. The tag only applies to future signups

FAQs

Q: Where do I find my Omnisend API key?

A: Log in to Omnisend, click your profile icon, go to Store Settings > Integrations & API > API keys, and click Create API Key. Make sure to select the Contacts permission before creating the key.

Q: What permissions does the Omnisend API key need?

A: The API key must have the Contacts permission enabled. This allows STOQ to create and update contacts in your Omnisend account. We recommend limiting the key to only the Contacts permission and naming it "Restock-private-key" for easy identification.

Q: Can I sync customers who signed up before I enabled the integration?

A: No. STOQ only syncs customers going forward from the moment you enable the integration. Previously signed-up customers are not retroactively synced to Omnisend.

Q: Will disabling the sync toggle remove contacts from Omnisend?

A: No. Turning off the toggle only stops new contacts from being synced. Contacts already in your Omnisend account remain untouched.

Q: Does STOQ sync both email and phone contacts?

A: Yes. If a customer provides both an email and a phone number during signup, STOQ adds both as identifiers on the same Omnisend contact. If only one is provided, STOQ syncs whichever is available.

Q: What is the custom source property used for?

A: STOQ sets a custom property called source on each synced contact, with the value of your profile tag (default: restock-rocket). You can use this property in Omnisend to create segments that specifically target customers who signed up through STOQ.

Updated on: 13/04/2026

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