Use customer IDs through Magento APIs

The extension does not add a dedicated Customer ID REST route or GraphQL field. It extends Magento's existing data instead:

• Customer records use the EAV custom attribute customer_id.
• Orders expose the copied value as the OrderInterface extension attribute customerid.

Access remains subject to Magento's normal API authentication, ACLs and website scope.

Read a customer

Magento's standard customer endpoint can include the value under custom_attributes:

GET /rest/V1/customers/123
Authorization: Bearer <integration-token>

Relevant response fragment:

{
  "id": 123,
  "email": "purchasing@northstar-industrial.example",
  "custom_attributes": [
    {
      "attribute_code": "customer_id",
      "value": "B2B-01042"
    }
  ]
}

Customer search uses Magento's standard customer service contracts with the same attribute code. Writing customer_id through custom_attributes is restricted: only admin and integration API tokens may set it — customer and guest tokens get rejected on account create and customer/address repository saves. See Protected customer attributes for the shared mechanism. Test the exact payload against your Magento release and integration permissions before building a synchronization job.

Read an order

For a registered-customer order, the copied business number can appear in order extension attributes:

{
  "extension_attributes": {
    "customerid": "B2B-01042"
  }
}

The name is customerid, without an underscore, because Magento already uses customer_id for the internal customer entity relation. Guest orders normally have no copied Customer ID. The field names reference compares all three identifiers used by the extension.

Integration ownership

Choose one owner for customer-number creation:

• If Magento owns it, let automatic assignment run and send the resulting customer_id to the ERP or CRM.
• If the ERP owns it, leave automatic assignment off during import and write the ERP value to customer_id.

Duplicate values are rejected — across all websites when ID range is global is enabled, otherwise within the customer's website. Imports should handle the validation error instead of silently generating a replacement.

There is no module-specific GraphQL schema. A GraphQL integration needs a separately implemented field or another supported integration layer.