What is spam?
The term “spam” originated from a 1970 Monty Python sketch (see for yourself!) and was soon after adopted to describe the “use of electronic messaging systems to send unsolicited messages (spam), especially advertising, indiscriminately.” (http://en.wikipedia.org/wiki/Spamming).


Everyone hates having their inboxes flooded with spam, and email clients are now increasingly better at filtering out the trash. However, many times, valuable emails (especially ones sent to large contact lists) get mistaken for spam. We work with many international clients that send communications to hundreds or thousands of contacts. Avoiding the dreaded spam folder is always on the back our minds.

What does StoneShot as an ESP do from a deliverability perspective?
We have a system in place to assist the delivery of emails being sent from the StoneShot app to a contact’s email client. From the back end development to how we design and format emails, everything counts when it comes to making sure our communications aren’t mistakenly labeled as spam.

Normally, emails are sent from a domain that belongs to one of our clients; in these instances it’s important for the recipient servers to know that it’s okay for the StoneShot servers to send emails on behalf of this particular domain. A client would update their SPF (sender policy framework) record contained within their DNS settings with details provided by StoneShot. This, in turn, authorises StoneShot servers to send emails from the domain on both SPF and Sender ID checks.

StoneShot also uses a more secure way of authenticating email messages by implementing Domain Keys and DKIM. Emails set up in this manner have some code embedded into an email itself that essentially makes it very difficult for other parties to forge. This code is injected into the email from the StoneShot servers so clients do not have to worry about managing this themselves.

Besides authenticating servers and emails, it’s also important to keep an eye on mail flow and any bounces that might occur. No matter how clean the content of an email, the majority of mail servers will still block any server trying to send a large amount of emails to its recipients. The StoneShot deliverability team monitors these emails and adjusts the server rules for mail.

The deliverability team also investigates the causes of bounces and monitors several blacklist sites. Any issues that crop up are investigated and false positives on these blacklist sites rectified.

In addition to the measures we take on the server/deliverability level, there are a few best practise rules we follow on the production side when creating email campaigns:

Avoid “spammy” content
All email clients have some sort of spam filter software, like Spam Assassin active in order to keep users from receiving spam in their inboxes. Spam filter software looks for indicators, e.g. certain keywords or phrases associated with spam like ‘CLICK HERE!’ or ‘FREE! BUY NOW!’. These criteria are weighed by assigning points to them and every occurrence adds to a message’s spam score. After a certain threshold is reached, the message is flagged as spam.

At StoneShot, we run our emails through spam checkers provided by the testing platforms Email on Acid and Litmus. These platforms check the emails in spam filters in use by the major email clients.

Accessibility aids spam avoidance
Creating emails that are coded using clean, efficient HTML and following accessibility rules, like using live text instead of images where possible and providing alt text for images, will not only help users read an email with accessibility software like screen readers but is also useful for spam avoidance. Spam filters will look for sloppy code and emails containing more images than text as most spammers don’t make the effort to create well-coded emails.

Don’t neglect plain-text emails
Send emails as multi-part MIME, which means they contain both a HTML and plain-text version. The email client then displays one of these two versions based on the end user’s preferences. The HTML version is shown the majority of the time so you might say, why bother with plain-text?  Well, it will help you fight the spam filters since they prefer it if a plain-text version is present and if it matches the HTML version.

Unfortunately, we can’t completely avoid our emails being labelled as spam. Overzealous spam filters and end users’ preferences might mean that a small number of messages end up in junk. We do, however, do everything possible on the server and production side to keep this number as low as possible.

If you have any questions or would like to find out more then drop us an email at engage@stoneshot.com.