XpressDox makes use of the industry standard OAuth 2.0 Authorization during its integration calls to DocuSign, NetDocuments, iManage and other file systems. This article contains some OAuth 2.0 resources.
What is OAuth 2.0?
“The OAuth 2.0 authorization framework enables a third-party application to obtain limited access to an HTTP service, either on behalf of a resource owner by orchestrating an approval interaction between the resource owner and the HTTP service, or by allowing the third-party application to obtain access on its own behalf.”
OAuth 2.0 Explanation and video resource: