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Direct Mail:API and SMTP FAQs

Last Updated:Dec 25, 2025

What are the differences between sending emails using an API and SMTP?

  • Simple Mail Transfer Protocol (SMTP)
    SMTP is a standard protocol for transferring email. It sends emails between mail servers or from a client to a mail server. SMTP is the fundamental protocol for sending email over the Internet.

  • Application Programming Interface (API)
    An API is a method of sending emails by calling the HTTP/HTTPS interfaces provided by Direct Mail.

  • Use SMTP for more customization options.

  • Use SMTP if your emails contain attachments.

  • Use the API to integrate with systems that require an API or for high call frequencies.

References

Three ways to send emails