Using REST API, how do you list all the Workflows in a SharePoint 2013 Site Collection?
Not sure if it lists all workflows for subsites, and I don't think it lists 2010 type workflows, only 2013 type workflows, but a place to start would be:
That does require a
POST and a valid form digest value, which you can either get off a page, or from
/_api/contextinfo (which also requires a
POST, but doesn't need the form digest).
If it doesn't list workflows for subsites, you could always just work down the tree by getting all subsites
and then query each of those for their workflows.