Spamming is the use of messaging systems to send an unsolicited message (spam). There are many different reasons why your sent emails might end up in the spam folder and this article explains how you can prevent it from happening.


Spam prevention
Good practices
Dealing with emails landing in spam

Spam prevention

To make sure none of your emails end up in spam, you should use preventive tactics when it comes to email marketing.

  1. Make sure your contact list only contains those, who actually subscribed to your list. Don’t rent, share, or scrape email lists.

Sender reputation and email delivery are the sole responsibility of the sender, not the Internet Service Provider (ISP) or Email Service Provider (ESP). By renting, sharing, scraping, and co-registering email lists, you’re sending unwanted emails to recipients that have not agreed or consented to receive those messages. In fact, sending emails to such contacts won't bring you any revenue and also will damage your deliverability. All ISPs (AOL, Hotmail, Outlook, Yahoo, Gmail, etc.) monitor spam reports and the more you get the lower are your chances to land in the primary folder. Wondering what an acceptable spam complaint rate is? 0.1% is the rate you shouldn't exceed. If your rates are higher, make sure to make your 'unsubscribe' button is visible. Respect your recipients’ wishes and remember that unsubscribes are always far better than spam complaints.

Your recipients should agree to and look forward to receiving your messages. To collect such subscribers you can use Omnisend Signup forms.

2. Freshen up your email list regularly

You can start from the video recording or look through the instructions provided below.

Email Services like Yahoo, Hotmail, and Gmail have all been known to use engagement tracking to help detect and filter spam. ISPs track how each user is interacting with your messages. If a user is not opening or clicking these messages, then it is likely that the messages will go to spam for that user. The more users that react this way, the worse things get overall, hence, the smaller, more engaged email list is better than a huge, unengaged email list. Regularly monitor your email engagement across all users. To ensure the highest engaged list possible, remove inactive recipients (those who don’t open your emails). You can read more about this here: Inactive Contacts.

Also, make sure to remove bounced emails and role email addresses. It's recommended to check the list with our recommended service provider Mailgun.

The quality of your list is much more important and valuable than the quantity of your list. Clean up your list and watch your engagement and sender reputation grow!

Note! If your newsletter campaign will get more than a 4.0% bounce rate, our system will suspend your account automatically. Bounced emails get automatically removed by our system, but in order to reactivate your account, it is necessary to delete contacts that did not voluntarily subscribe to your brand, are old, inactive, or don’t have an opt-in record.

  1. Create an account in Mailgun

  2. You will need to export your entire contact list from your Omnisend Audience

  3. Go to Validations tab in your Mailgun account > Validate

  4. Check the exported list with the service

5. Download just checked, good contacts

6. Upload your clean list back to Omnisend and add a specific Tag when importing:

7. Proceed to Audience and filter those who don't have this tag you added via import. Save this segment:

8. Mark the 'Name' checkbox, proceed to "Select all the contacts" and unsubscribe those contacts. This way, you will be unsubscribing contacts that were not present in the "healthy" file:

Good practices

Using own domain for sender's email

An example - "[email protected]". You should be doing that. Email service providers (such as Yahoo, Gmail, AOL and others) are very picky if you are sending newsletters using their domains -,,,, etc. In most cases, they will put your newsletter in SPAM folder or reject it. In conclusion - don't use [email protected]. Use [email protected] instead. Read more about DMARC policy.

Practice good text-to-image ratio

Your campaign or automated email should not just contain images. Some spam filters check text-to-images ratio and it is important to keep it a healthy one. Providing two to four sentences per image helps give context to the ISP and your recipients.

Be aware of Gmail clipping

If your email is too large, it could be clipped by Gmail. Be sure to preview your message in a test email (or two!) and adjust the copy as needed.

Managing your domain reputation

Have you ever tried to send a lot of the same emails directly from your inbox trying to promote your products (before you started using Omnisend)? Then it is possible that your domain's reputation is compromised. You can check it here. Just enter your domain (i.e. and click "Blacklist check" to check if it is blacklisted.

If your sender's domain (or your store domain) is blacklisted, your emails will definitely land in spam. Getting it whitelisted should be the first step before starting your email marketing.

Avoiding spammy content

Some spam filters do not like the way content is being phrased. Take a look below at some common mistakes that should be avoided:

  • Excessive use of exclamation points!!!!!!

  • Using phrases like “Click here!” or “Once in a lifetime opportunity!”

  • USING A LOT OF ALL CAPS IN SUBJECT LINE AND IN BODY TEXT. Don't do that (especially in subject lines).

  • Sending a test to multiple recipients within the same company (your colleagues). It's possible that company’s email firewall will assume it’s a spam attack.

  • Hash-busting: Inserting random characters in the subject line or content to fool spam filters, e.g. “F.ree. p.r!z.e”

  • Be careful with words associated with the language of sales. You can still use them but don't use them too often. If overused, they may trigger spam filters and route your emails to junk folders. Risky words include: “prize”, “free”, “bonus”, etc.

Dealing with emails landing in spam

In case your emails start landing in spam, there are a couple of ways you can resolve this issue:

  • Make sure you are following all of the above mentioned best practices and preventive tactics.

  • If that does not help, please contact our support so we could check if there are any issues on our end. We might be able to offer to sign SPF and DKIM records, move you to a dedicated IP, move to another one, or send your sender's domain, and more. The particular steps depend on the case and would be recommended by our Deliverability team. Just note, additional charges may apply. 

You can find more information about deliverability, spam, and getting into subscribers' inboxes in our blog post about bounces. If you have more questions - contact us at [email protected].

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