lettre_email is used at run time in 10 crates (of which 1 optionally). It's used only as a dev dependency in 4 crates.

Depender (with downloads and own rev deps) lettre_email version
raider-server ^0.9
1 dead-man-switch ^0.9
zoom-lomax ^0.9
rss_emailer ^0.9
got-ya-id ^0.9
nebula_email ^0.9.2
rsmb ^0.9
sso ^0.9
morbo optional ^0.9
9.4K 21 imap dev ^0.9
3.7K 7 notmuch dev ^0.9.2
1 imap-patch-for-async-imap-lite dev ^0.9
smtp-dump dev ^0.9