BUG: Subscribe to webhook

GraphQL Admin API Troubleshooting
1

Hi ShopifyDev’s,

I’m getting weird errors when I try to subscribe to a webhook (2026-01). Via the GraphQL app installed on the store:

mutation CreateWebhookSubscription {
  webhookSubscriptionCreate(
    topic: INVENTORY_LEVELS_UPDATE
    webhookSubscription: {uri: "https://example.com"}
  ) {
    webhookSubscription {
      id
      topic
      filter
      uri
    }
    userErrors {
      field
      message
    }
  }
}

{
  "data": {
    "webhookSubscriptionCreate": {
      "webhookSubscription": null,
      "userErrors": [
        {
          "field": [
            "webhookSubscription"
          ],
          "message": "You cannot create a webhook subscription with the specified topic"
        }
      ]
    }
  }
}

SOLVED:

When I try via Postman. Exact same Query but different error:

{
  "errors": [
    {
      "message": "Field 'webhookSubscriptionCreate' doesn't exist on type 'Mutation'",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ],
      "path": [
        "mutation CreateWebhookSubscription",
        "webhookSubscriptionCreate"
      ],
      "extensions": {
        "code": "undefinedField",
        "typeName": "Mutation",
        "fieldName": "webhookSubscriptionCreate"
      }
    }
  ]
}

And in Postman it works when I use the REST api:

{
  "webhook": {
    "address": "https://example.com",
    "topic": "inventory_levels/update"
  }
}

x-request-id: 58b18e93-ee19-4a4c-a941-e749b09bc71a-1771855639

2

@AdminGh, can you please try with topic: "VARIANTS_IN_STOCK"?

wrong

topic: VARIANTS_IN_STOCK

correct

topic: “VARIANTS_IN_STOCK”

3

@remy727 does not matter, also tried:

INVENTORY_LEVELS_UPDATE same error.

4

@AdminGh, can you please confirm if you selected the required scopes while installing GraphQL app?
For example, read_inventory.

5

The first part sounds like the scope issue Remy mentions, but for Postman, it reads like you’re hitting the wrong API version endpoint or you’re calling the Storefront API instead of the Admin API. If you’re using a URL without `/admin/`, you’ll be hitting the Storefront API, which doesn’t have webhook mutations.

6

@HookdeckGareth @remy727

Thanks for the help!

  1. GraphQL app: Yes i can subscribe to INVENTORY_ITEMS_CREATE for example…
  2. @HookdeckGareth thats it! Its indeed an url without the admin part. Thx!