Log In

If you’re experiencing slow sending speeds, here are a few important things to consider…

The SMTP protocol can often require many “round-trip” cycles, where your computer/server has to wait for a response from us, and vice versa. Normally the best way improve slow sending speeds is to do the following:

Example software that supports the above is Postfix.

If you are sending emails that are quite large (e.g. emails with large images or attachments), then the upload speed of your internet connection can limit your sending speed. Consider the following:

To get a rough estimate of your likely upload bandwidth capacity, you can perform a speed test at Speedtest.net. The important figure to pay attention to is the Upload Speed.

speedtest.png

Keep in mind that if you are sending a 100KB attachment, your email will be larger than 100KB:

  • Attachments grow by about 40% when encoded using Base64.
    Attachments grow by a variable amount (0-220%) when encoded with Quoted-Printable, depending on how much is ASCII and how much is not.

If you are experiencing slow sending speeds when sending to email addresses at your own domain name(s), you may need to safelist our IP address ranges with your incoming (MX) server.

Leave a Reply

Your email address will not be published.

Ready for better email delivery?

Try SMTP2GO free for as long as you like:

Try SMTP2GO Free → Paid plans available for over 1,000 emails/month.
×

Ready for better email delivery?
Try SMTP2GO free for as long as you like:

Try SMTP2GO Free See Pricing