Sign in with the key that owns the mailbox. Inside: wallet-to-wallet messages on the dfmi chain, delivery out to ordinary inboxes, and a contact book that never leaves this browser.
Signing in costs nothing and moves nothing. The wallet signs a challenge issued by exchange.dfmi.me; the server returns a bearer token that expires on its own.
Connected-session--
address0x…name-
alias-
Inbox0
Contacts
Saved in this browser, under the signed-in address. Nothing is uploaded.