Board Thread:The Quarters - Q & A/@comment-176.189.218.153-20170303141551/@comment-25085701-20171102201249

Try this:

curl https://habitica.com/api/v3/tasks/user?type="completedTodos" -s -X GET --compressed -H "Content-Type:application/json" -H "x-api-user: " -H "x-api-key: "

Works for me on my list.