provide minimal API access for mail transport agents
some mail transport agents (e.g. exim4) have to decide whether to route a message to schleuder or not, without having privileges to access the schleuder installation directly.
It'd be great if there was a minimal-privilege level for the schleuder api that would allow only information about what e-mail addresses schleuder expects to accept. Then the MTA could use that api query to decide whether to route mail to schleuder or not.
the postfix integration we already have works around this because it's running as a user with enough privileges to directly query the sqlite3 schleuder database, fwiw.