Simple Mail Transfer Protocol (SMTP), a communication protocol use by email servers for transmission.

The Simple Mail Transfer Protocol (SMTP) is a communication protocol for electronic mail transmission. As an Internet standard, SMTP was first defined in 1982 by RFC 821, and updated in 2008 by RFC 5321 to Extended SMTP additions, which is the protocol variety in widespread use today. Mail servers and other message transfer agents use SMTP to send and receive mail messages. SMTP servers commonly use the Transmission Control Protocol on port number 25.

User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and typically submit outgoing email to the mail server on port 587 or 465 per RFC 8314. For retrieving messages, IMAP and POP3 are standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync.

Run an email deliverability check

1. On the dashboard menu, click on the top right button “Run a new test”.

2. Send an email you want to test to the address showed in the pop-up and click on the "Next" button.

3. Wait for the results to be processed, it can take up to 2 minutes.

4. Get your complete deliverability report.

5. You successfully ran an email deliverability test!

If you encounter any difficulties to test your SMTP inbox, do not hesitate to contact us directly on our live chat Intercom.

Check your email deliverability & fix your issues.