MailGun, SendGrid, or Mailjet for backend email delivery

I have a non-ejected react-native Expo project that I am wanting to send a background email to some user (like an invitation email). For a non-ejected project, is there a proven service that can be accessed via their API that works? I’m considering MailGun, SendGrid, or Mailjet for this, but was hoping someone could confirm that they have one of these services working before committing.