Yes. You can use UpOrder and an Email Service Provider (ESP) together.
They usually solve different email problems. UpOrder is focused on Shopify notification emails, while ESPs such as Klaviyo, Omnisend, Mailchimp, and similar tools are usually used for marketing campaigns, newsletters, customer segments, forms, and marketing automations.
What UpOrder does
UpOrder helps you customize the Shopify notification emails that are sent after Shopify events, such as order confirmations, shipping updates, refunds, account emails, and other customer notifications.
When you publish an UpOrder template to Shopify, Shopify still triggers and sends the notification email. UpOrder controls the design and content of the template that Shopify sends.
This is why using UpOrder for Shopify notifications does not create a duplicate email by itself. You are updating the Shopify notification template, not creating a second notification send.
What an ESP usually does
An ESP is usually where you manage marketing email and lifecycle messaging outside of Shopify's built-in notification templates. Common examples include newsletters, product launches, sale announcements, welcome series, winback automations, post-purchase education, and segmentation-based campaigns.
Some ESPs can also send certain transactional or order-related emails, but the setup, supported email types, approval requirements, and Shopify plan limitations vary by platform.
When duplicates can happen
Duplicate emails can happen if another app or ESP is configured to send its own order, shipping, refund, or account notification while the matching Shopify notification is still active.
For example, if Shopify sends an order confirmation and an ESP also sends a separate order confirmation for the same order, the customer may receive two emails.
If you are replacing a Shopify notification with a separate ESP-sent email, check whether Shopify allows that specific notification to be turned off for your store and plan. Some Shopify notifications may not be fully disableable on all Shopify plans.
When to use UpOrder
Use UpOrder when you want Shopify's notification emails to look on-brand, include richer template content, and support post-purchase merchandising such as product recommendations, discounts, navigation, and other components inside the Shopify notification itself.
When to use your ESP
Use your ESP for marketing campaigns and automations that are separate from Shopify's required customer notifications. This might include newsletters, promotions, customer segments, browse or cart automations, review requests, replenishment reminders, and other lifecycle campaigns.
Best practice
Use one system as the source of truth for each email type. If Shopify is sending the notification, use UpOrder to customize that Shopify notification. If an ESP is sending a separate transactional or order-related email, make sure you understand which Shopify notification should remain active and which one should be disabled, if Shopify allows it.
For more detail on how Shopify notification emails are triggered, see: When and how are Shopify notification emails triggered and sent to customers?
For Shopify's notification documentation, see: Store notifications.
Please reach out to [email protected] or through the in-app chat if you have any questions.