+1 against Sendgrid. They were a pretty good service when we signed up with them ~5 years ago (Paid plan with private IP), but ever since the Twilio acquisition

+1 against Sendgrid. They were a pretty good service when we signed up with them ~5 years ago (Paid plan with private IP), but ever since the Twilio acquisition their customer support and technical reliability has gone through the floor. Postmark is a phenomenal service and I'll be using it for every transactional email service I need going forward.