Hi,
I’ve been debugging an issue where the CUSTOMER_TAGS_ADDED webhook topic does not always fire when tags are added manually through the Shopify Admin UI. After thorough testing I’m confident this is a bug.
Setup:
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API version: 2025-10
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Webhook registered via GraphQL (webhookSubscriptionCreate)
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Topic: CUSTOMER_TAGS_ADDED
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Delivery verified using webhook.site
What works:
Adding a tag via the tagsAdd GraphQL mutation fires the webhook correctly and immediately.
What doesn’t work:
Adding a tag manually through the Shopify Admin UI (opening a customer, adding a tag, saving) produces no webhook event at all.
Steps to reproduce:
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Register a CUSTOMER_TAGS_ADDED webhook via GraphQL webhookSubscriptionCreate
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Open a customer in the Shopify Admin UI, add a tag and save
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Observe: no webhook fires
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Add a tag to the same customer via the tagsAdd GraphQL mutation
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Observe: webhook fires correctly
Expected behavior:
CUSTOMER_TAGS_ADDED fires regardless of whether the tag was added via the Admin UI or the API.
Why this is a critical issue:
Since 2025-01, tags were removed from the CUSTOMERS_UPDATE payload, and CUSTOMER_TAGS_ADDED was introduced as the replacement. But if it only fires for direct tagsAdd API calls and not Admin UI actions, there is no way for apps to react to tag changes made by merchants manually — which is a very common use case. This is a significant regression with no workaround.
Has anyone else reproduced this? Can Shopify confirm this as a bug?