On May 16, 2017 at 1:05 AM Ory Drilon <odrilon@fastmail.com> wrote:

Hi, is there a way to arbitrarily filter out mails at the moment the IMAP request is made, based on properties of the IMAP session and the mail itself?

All the filtering methods I find occur during delivery time.

imapsieve: https://tools.ietf.org/html/rfc6785

Although obviously triggering filtering based on a FETCH itself doesn't make much sense and isn't supported by imapsieve (triggering based on flag change *caused* by FETCH is supported however).

michael