Sending Email with Laravel, SendGrid, Beanstalkd and Go
b.z19r.com
b.z19r.com
I can see why you'd do it if you want your app to have a certain level of responsiveness, but otherwise this seems a bit like overkill.
One other option would be create an email api service in Go(or node or whatever) that that just returns a 200 instantly and sends the email after that. It would be as fast as dropping a msg into the beanstalkd queue with fewer moving parts.
http://sendgrid.com/docs/Integrate/Mail_Servers/postfix.html