> ## Documentation Index
> Fetch the complete documentation index at: https://www.plain.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# upsertCustomerGroup

> Create or update a customer group identified by `customerGroupId`, `customerGroupKey`, or `externalId`. If a matching group is found it is updated and the result is `UPDATED`; if data is unchanged the result is `NOOP`; otherwise a new group is created and the result is `CREATED`. Note: using `customerGroupId` as the identifier returns an error if the group does not exist. Requires `customerGroup:create` and `customerGroup:edit` permissions.