Recommendations and Best Practices for avoiding Spam Blocking

Spam flagging can be triggered for several reasons. A common trigger is an analysis of the content you are sending. Everything is important, from the subject line of your emails, to the font and color of the characters you are using. This guide covers our recommended best practices for avoiding spam blocking.

Avoid “spammy” content

One rule of thumb is to avoid using Spammy Words. Here are some examples of content commonly flagged as spam:

  • Using the color red in your content.
  • Using “Money” or “$$$” (dollar signs) prominently in the subject line.

Images vs words

Another good practice would be to keep a low image to word ratio. Try to send your customers newsletters that are not just pictures, even if the pictures have text incorporated. We recommend having at least 40% of your email content be composed of words, as this is a known filter when it comes to spam control.

Poor Customer Engagement

Another reason your content may be flagged as spam is poor customer engagement. This is often seen when users are sending from an out-of-date emailing. Here are a few good techniques we can recommend:

Purchased contact lists: The biggest mistake we see users make is attempting to buy contact lists for sending email. Buying lists goes against our company policy, which can result in your account getting suspended.

User allow list: Having your contacts automatically allow your messages by add your address to their address book or contact list is a great way to maintain a good and productive customer engagement. Not only does this allow you to reach your customers more reliably, their engagement with your content will improve your standing with the recipient server as well. This also makes it easier to reach out to new potential customers.

The easiest way to request this is to include a single line message in your Welcome newsletters or new Product campaign. Here's an example:

Take a quick moment to add the email address *Your email* to your address book or contact list. That way, you'll always be sure that you aren't missing important information or offers from us.

Sunset policy

Incorporating a Sunset policy is another healthy maintenance option for your email lists. This will help to ensure you maintain an engaged list, adding to your domain’s sending reputation. For more details, see How to Create and Execute an Email Sunsetting Strategy (SendGrid blog).

Check your email signatures

Another possible issue for spam flagging could be that your email signatures don't successfully pass Sender Policy Framework (SPF) or DomainKeys Identified Mail (DKIM) checks. Alternatively, they may pass, but are signed by our server so the email is tagged "via Sendgrid". To resolve these issues, we strongly recommend users setup Domain Authentication. For more details, see How to Set up domain authentication.

Poor IP Reputation

Poor IP reputation is the trickiest issue to resolve. Although we have very strict filters in place to prevent bad senders, they may sometimes slip through the cracks, and can cause our IPs to be temporarily blocked. When this occurs, and the issue is reported to us, we begin our mitigation process. While our goal is to make this process as fast as possible, there are no ETAs for our delisting requests. We ask for your patience in these situations.

Users looking to avoid shared IP issues will want to look into one of our Pro packages that provide a dedicated IP addresses. With a dedicated IP, you will be in full control over the content and quantity you send from that specific IP.


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