Email rendering is done within Laravel

First thing I would look into is to store templates on the Mandrill side and just pass the data. That would reduce the size of the API transfer alot. A simple well formatted email (I use Inky) eats up 25kb. The dynamic data makes up for what, 5% of that?

Every single email is different? I mean do you really have to salute the guy by name? Or can you consolidate by JOB and dispatch multiple recipients to Mandrill in one api call?

You have to prioritize. If you have dynamic data on the email body (Hello Patrick, there is a new job for you nearby) maybe remove "Patrick"?

Would you send less emails consolidation by PERSON BEING ALERTED and dispatching this multiple alerts, or consolidating by JOB and dispatching to multiple persons? The latter would be easier to template I think. Less data being transfered.

Thats all I can think now.

Best of luck.