The sendmail transport sends the email using the local sendmail command.
use lettre::sendmail::SendmailTransport; use lettre::{SimpleSendableEmail, EmailTransport, EmailAddress}; let email = SimpleSendableEmail::new( EmailAddress::new("user@localhost".to_string()), vec![EmailAddress::new("root@localhost".to_string())], "message_id".to_string(), "Hello world".to_string(), ); let mut sender = SendmailTransport::new(); let result = sender.send(&email); assert!(result.is_ok());