How to Avoid the Spam Folder: 10 Practical Fixes

Ending up in the spam folder is the worst nightmare of every marketer. If you’re not careful, it may happen even if you’re sending relevant emails to the audience that agreed to receive messages from you. Imagine your neatly crafted campaigns landing straight in the trash. Doesn't sound good, does it? Luckily for you, there are a few things you can do to avoid the spam folder. But, let’s first dig into what spam is and why your emails may be marked as spam.

What is SPAM?

Email SPAM is also referred to as junk mail. These are all unsolicited messages that are most often sent in bulk and for commercial purposes. They can also be sent as a malicious attempt to gain access to your computer. These may include fake antivirus warnings, spoofing attacks, and money scams.

Why do legitimate emails go to the SPAM folder?

Let’s assume you’re sending legitimate and wanted emails, but somehow, they end up in the SPAM folder. Why does it happen? There are a few reasons for that. 

First of all, whenever you send an email, it is scanned by spam filters, which are supposed to protect your audience and detect any dangerous or unsolicited content. What can make them suspicious is when you have not authenticated your domain or it has a bad reputation. The same goes for your IP address. If it has been used for spam in the past, it will no longer seem legitimate to spam filters. 

Your emails may also go straight to the spam folder if you don’t keep your list clean or if your sign-up forms are abused by bots. It may also be the case when your “From” address is not accurate, your subject lines are misleading or you use spam trigger words. Spam filters may also mark your emails as spam if you include suspicious attachments, your content is not relevant or you use too many images.

As you can see, there may be various reasons why your emails could be marked as spam. Let us go through the best practices on how to avoid the spam folder.

How to avoid the SPAM folder?

If you send more than 5,000 messages a day to any one of these providers, you are treated as a bulk sender and a specific set of rules applies:

1. Authenticate your domain

Authenticating your domain is how mailbox providers confirm you are a reliable and legitimate sender. Domain authentication will ensure that emails are not perceived as spam and, therefore, reach your recipients. To verify your domain, you need to add authentication records like SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail). Since February 2024, Google and Yahoo have also required a DMARC record, and Microsoft introduced the same requirement in May 2025. We cover what each provider asks for in detail here. Once authentication is set up, you can also add a BIMI record so that your logo appears next to your outgoing emails. And it is worth remembering that a free domain is generally not recommended, because it offers a lower level of security than a paid one.

The consequences differ by provider, and Microsoft's are the bluntest. Google and Yahoo throttle or reject mail from senders who fall short. Microsoft has rejected non-compliant mail outright since 5 May 2025, returning a 550 5.7.515 Access denied error rather than quietly filing the message in junk, so a configuration problem there produces a bounce, not a mystery.

2. Build your own email list

No matter how tempting buying an email list can be, it is illegal and will send your emails straight to spam. Sending emails to addresses that didn’t confirm they agreed to receive emails from you will result in an unengaged audience. It will also ruin your sender reputation, as spam filters will see you as a spammer. Building your own email list may take longer than buying a ready list, but will be more rewarding and bring user engagement.

3. Use double opt-in

As we speak about building an email list, let’s not forget about using double opt-in. It’s a great practice to make sure someone who signed up for your list really wants to receive emails from you. Once your subscriber provides you with their email address, they receive a confirmation email. As they have to give consent for their subscription, which requires action, it is proof you’re gaining a valuable lead. It will also prevent bots from spamming your sign-up forms.

4. Clean your email list regularly

Email lists do not stay up-to-date forever. Some contacts become invalid, inactive, or stale. That’s why it's crucial to clean your email list regularly. Imagine someone no longer wants to read your emails, but they don’t unsubscribe. They do not open or interact with your content or, even worse, mark your emails as spam. Your open rate and spam rate will increase, destroying your sender reputation. You can send a re-engagement email as a final effort  to connect with inactive recipients. If you decide to delete inactive contacts or those who have complained about your content from your list, your email list will become healthier and more up-to-date. Sending to invalid contacts, in turn, also increases your bounce rate, which also causes damage to your reputation and email deliverability.

5. Monitor your sender reputation

Speaking of reputation, there are a few indicators to help monitor it. The most important is whether your subscribers mark your emails as spam. Google and Yahoo expect bulk senders to keep the spam complaint rate below 0.10% and to never reach 0.30%. And unlike most email metrics, those are enforced limits rather than targets. You can track your complaint rate and your domain reputation for free in Google Postmaster Tools, which is the closest thing to seeing your sending the way Gmail sees it.

You should also keep an eye on your email bounce rate. Aim to stay under 2%, and treat anything above that as a warning rather than a normal fluctuation - a rate climbing toward 5% signals a list quality problem that mailbox providers will notice before you do. Hard bounces matter more than soft ones here, because a list carrying invalid addresses is read as poor hygiene.

Finally, check whether your domain or IP address has been added to a blocklist. Lookup sites like MXToolBox will tell you, and will usually point you to the delisting process for each list.

6. Be compliant with anti-spam laws

Since sending advertisements via email has become so popular, there had to be regulations to govern the sending of commercial messages. In the United States, the CAN-SPAM Act of 2003 requires you to identify your location, describe the message accurately, and give recipients a straightforward way to opt out. In the European Union and the UK, GDPR and the ePrivacy rules go further: in most cases you need consent before you send at all, you need to be able to show how and when that consent was given, and recipients can ask you to delete their data. Canada's CASL is stricter again on consent.

In practice, if you have subscribers in more than one region, build for the strictest regime you are subject to rather than maintaining separate standards. It is simpler, and consent-based sending produces fewer complaints anyway, which is the point of this article. Because the details vary and change, treat this as orientation and have your own legal or compliance review confirm what applies to your list.

7. Send relevant content

It may sound obvious, but sending relevant content is essential in nurturing the relationship with your subscribers, keeping them engaged, and avoiding the spam folder. You may send emails about updates on your products, helpful tips, and educational content. Make sure you offer the content that is useful and desired by your recipients. This will help your audience stay committed and engaged, and you’ll be less likely to be seen as a spammer.

8. Avoid spam trigger words

We all want to come up with an original subject line that will make people open the email as soon as they see it. But, at the same time, we should avoid so-called “spam trigger words”, which are risky and increase the chance of your emails landing in the spam folder. The same applies to the entire text of the email. Make sure you don’t sound pushy, suspicious, or desperate in your messages.

9. Send test emails

Remember to always test your emails before sending them to your audience. Taking this extra step will allow you to see what your message looks like in the inbox, including if it’s readable and whether everything loads correctly. You can also use email testing tools like Litmus or Email on Acid to check how your emails look in different email clients.

10. Use spam checkers

To keep your emails from landing in the spam folder, you can also use spam checkers. Tools such as Mail Tester or Mailreach scan your message in search of any spam content or malicious links. They often also inspect your sending domain or IP address and check its reputation. Then, you get a spam score of your email and insights into what you can do to improve your deliverability.

Avoiding the spam folder - wrapping up