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Robly Email: How SPAM Filters Work

Our goal at Robly is to get as many emails as possible to your subscribers inboxes. In many cases, SPAM filters stand in the way of that objective.

We think that somewhere between 10 and 20 percent of all emails sent get lost before they reach their destination, mostly because of SPAM filters that are set with a threshold that’s too low.

Looking at one of the largest, most popular SPAM filters — called Spam Assassin — can give you an idea of how SPAM filters work. Robly runs your email through Spam Assassin’s spam test, and if your score is above our threshold of 5, we won’t send it.

If you score above a 5, you’ll see in your pre-flight check-out that you’ve failed the SPAM test, and you can go back to the Drag-and-Drop Editor to change your content to lower your score.

How SPAM Filters Work

A SPAM filter will look for “spammy” words, phrases, or characteristics of an email, and for each “offense” it will give you points. Subject lines that are ALL CAPS or have g a p p y t e x t or talk about things that are FREE or tell you to CLICK HERE! all fall under the realm of what’s considered “SPAMMY.” For more on SPAM, click here.

Here are some examples of Spam Assassin’s scores for various offenses:

  • Weird repeated double-quotation marks (1.353 points)
  • Mentions generic viagra (1.933 points)
  • Subject contains FREE in CAPS (.011 points)
  • Subject GUARANTEED (1.749 points)
  • Talks about millions of dollars (1.594 points)

SPAM filters are constantly learning what SPAM is, and are constantly evolving as SPAM evolves.

Ways To Avoid SPAM Filters

Several common mistakes are made by legitimate, non-SPAMmy senders that gets their mail caught in SPAM filters. Here are the most common errors:

  • Avoid “Click Here” or “FREE!” in subject line.
  • ALL CAPS in subject line is BAD.
  • N o g a p p y t e x t.
  • Do not use the word “test” in the subject line.
  • Don’t mention any of the forbidden industries in our TOS.
  • Make sure your email isn’t an IMAGE ONLY.
  • Avoid red or green fonts.
  • Don’t send a test to multiple people at the same company. Firewalls will assume this is SPAM.
  • Don’t design an HTML email in Microsoft word and try to use it in Robly. It will be broken, we guarantee it.

How do I know if my emails were caught in SPAM filters?

First, check out your open rate. If there was a dramatic drop-off compared to that list’s average, you probably did something unintentionally SPAMMY.

Next, check your bounce report. Look through your hard bounces to see what type of SMTP replies you were given.

Robly is in feedback loops with all of the major ISPs. When an abuse complaint is made, that ISP sends us an alert, we tie that alert to your account, and we automatically remove that subscriber from your list so that you can avoid abuse complaints happening in the future. You will see any ISP abuse alerts in your newsfeed.

Update Your SPF Record

We highly recommend updating your SPF record prior to sending in Robly. This is done on the back end of your website’s domain – it’s what gives Robly permission to send on your domain’s behalf. When you don’t do this, your domain sees that you’re sending via Robly without the proper permissions and therefore your email will look more suspect to spam filters.

In summary, SPAM filters are just automated algorithms that look for spammy characteristics and add them all up. If you don’t want to get caught in SPAM filters, don’t create emails that look like they came from a spammer. If you want to see what SPAM looks like, check your junk mail folder and make sure your campaign is the opposite of what’s inside.