title: How to send emails in golang without any smtp server
body: <p>I want to send bulk mail from a server application written in golang. I just don't want to use any third-party smtp server to avoid usage quota limitations. </p>
  
  <p>How can I send email without a smtp server? Is smtp package in standard library can help me? All example I see using the smtp package requires a third-party smtp server to send email.</p>