You can use `/users/{ids}/associated`

Try it for [your network account](http://api.stackexchange.com/docs/associated-users#ids=4337810&filter=default&run=true)

> Returns all of a user's associated accounts, given their account_ids in {ids}.

>{ids} can contain up to 100 semicolon delimited ids, to find ids programatically look for account_id on user objects.

>You can filter the network_users returned by this method with the types parameter. Specify, semicolon delimited, main_site or meta_site to filter by site.

> This method returns a list of network_users.