I got the following from fiddler whenever I try to login to dropbox.
[{"uid": 663175210, "sess_id": 272608865417613682242215474540606531660, "expires": 1495277184, "team_id": 2059286, "role": "work"}]
Notice that uid is being passed. I did some google and found that the uid is The Dropbox user ID of the authorized user. Is there any way i can get the user email id (used to login to dropbox) using dropbox API, given that i have the corresponding uid?