Hi,
You can refer to the Analytics logs as follows to identify the webservices requests:
Analytics > Admin > Logs > Usage & Access Logs
Document Reference: https://docs.adobe.com/content/help/en/analytics/admin/admin-tools/logs.html
Filter these with keywords such as 'API operation' or 'WebServices' under Event field. Under Login header you will find the username running the requests.
Hope this helps!
Thanks,
Saumya