title: Difference between PHP mail function and using email delivery service like Sendgrid, Mandrill
body: <p>I am building a program and need to send multiple emails based on certain events. I have coded using the PHP mail function but was advised against its use.</p>
  
  <p>Can somebody explain the difference between the workings of the PHP mail function vs using commercial services like Sendgrid, Mandrill etc? Why would one use these services when I can very well use the free PHP mail function to send mails?</p>