Looking for an Email Follow Up product

Hi all,

I am looking for an email app that allows me to readily and reguarly email the users of my SaaS.

I want to have certain segments of users such as:

  1. If a user has joined and never logged in, then I follow them up with an email in 24hrs asking if everything is alright.
  2. If they are a paid member then I wish to email them monthly asking “how it’s going”
  3. If they have logged in and not added some details I want to remind them on day 3

I know there are lots of emailing scheduling apps out there - but before I role my own “user segment regular follow ups” I was wondering anyone knows of an app out there that does what I want?