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Improve your cold emailing deliverability

Ways to Avoid Spam Filters in Your Cold Email Outreach

Updated this week

Have you ever imagined achieving a cold emailing outreach strategy with zero bounced emails?

In this article, we'll provide insights on how to bypass spam filters when sending cold emails to potential prospects. You'll gain valuable tips, best practices, and actionable strategies to enhance your campaign's performance. 🚀

👩‍🏫 Definitions

⛔️ Spam Filters

Email Service Providers (ESPs) implement spam filters to prevent their customers and users from receiving unwanted and poor-quality emails.


As a cold emailer, it's important to view spam filters as a positive tool. When your emails successfully reach your prospects' main inbox, they're less likely to be automatically flagged as spam.💣

👁️ SPF

The SPF (Sender Policy Framework) allows your domain provider to verify that the sender of an email from your domain is authorized to do so, ensuring that only trusted individuals or tools can send emails on behalf of your domain. 👍

✍️ DKIM

DKIM (DomainKeys Identified Mail) allows your domain provider to digitally sign a portion of the email, which your email service (such as Google) can then verify to ensure the message genuinely originates from the correct domain.

⚔️ DMARC

DMARC is a guideline for email recipients on how to handle messages if SPF and DKIM verification fail (which is why DMARC should be set up after SPF and DKIM).

🚨 If these settings aren’t properly configured, your email setup will be seen as "insecure," making it vulnerable to misuse by spammers. This can drastically impact your email deliverability!

🚀 Actions to avoid spam filters

1️⃣ Assess your domain's health

You can use the Google tool to your domain's health and improve it!

💡Your Domain Name is the part of your email address after the @, i.e zeliq.com for an email address like [email protected].

Your test results will tell you:

1. What's wrong with your email that could make it land in the spam folder. Everything is explained so even a beginner can understand.

2. How to fix those problems to maximize your email open rates, clicks, responses, and sales. 🚀

2️⃣ Set up secondary domains

💥 Secondary domains are super helpful for cold email marketing because they:

  • Divide the email-sending load

  • Improve deliverability

  • Protect your primary domain's reputation

  • Prevent your primary domain from being blacklisted

For instance, if you're sending 1,000 emails daily, it's a good idea to split them into smaller batches—no more than 50 emails per address.

But instead of creating 20 email addresses under your primary domain, it's smarter to buy secondary domains and create 2-3 email addresses from each one.

So, to send out 1,000 emails, you’d need around 7 secondary domains. This way, you keep your emails deliverable and your primary domain safe and sound.

You can buy secondary domains on websites like:

  • GoDaddy

  • Bluehost

  • Hostinger

  • Domain.com

3️⃣ Add your SPF, DKIM, and DMARC records to all your domains

❤️‍🔥 Make sure you disconnect and then reconnect your email account to ZELIQ once you have made changes those changes.

Most spammers don't bother setting up their email accounts properly before sending out tons of spam. By taking a few minutes to configure your account correctly, you'll boost your email deliverability and reduce the risk of getting caught in spam filters.

Luckily, setting up these records isn't too technical. Just follow the steps provided by your Email Service Provider (ESP).

Click on the following links to set up SPF and DKIM on Gmail and Outlook. And those links to set up your DMARC on Gmail and Outlook.

👁️ SPF

👉 Step 1 - Go to your hosting provider's DNS configuration;

👉 Step 2 - Select "DNS Management";

👉 Step 3 - Fill in the fields. Most importantly, in your SPF field, specify “include:_spf.google.com”.

✍️ DKIM

👉 Step 1 - Generate a DKIM Key Pair: Visit a reputable DKIM key generator, such as “https://dkimcore.org/tools/”. Once there, select the option to generate both a private key and the corresponding public key. Don't forget to save the private key safely. It must never be made public;

👉 Step 2 - Add DKIM records to DNS: Log in to your domain hosting platform (such as GoDaddy, Bluehost, or Namecheap). You'll usually find a section entitled “DNS Management” or “Domain Management”. In this section, look for an option to modify or add a “TXT record”. Enter the public key you generated in the previous step in the value/content field of this record.;

👉 Step 3 - Depending on your mail server or ISP (e.g. Gmail, Outlook, SendGrid), there will be an option to “Enable DKIM” or “Authenticate e-mails”. During this procedure, you'll be asked to provide the private key generated in step 1. By entering this key, you ask the server to sign outgoing e-mails with this key.

🍬 Pro Tip: Check the DKIM settings on your mail server or ISP regularly. Check that DKIM signatures are still active and have not expired. For optimum security, consider refreshing and updating the keys every year.

⚔️ DMARC

👉 Step 1 - Create a DMARC record: In the DNS Zone of your mail server, a TXT record is added to your domain's DNS. It specifies the DMARC policy for your domain.

👉 Step 2 - Specify the policy: The policy can be :

  • none: Take no specific action; just collect comments.

  • quarantine: Place suspicious e-mails in the spam/junk folder.

  • reject: Simply reject suspicious e-mails.

👉 Step 3 - Fill in the desired DMARC record

🤝 Examples of common DMARC records:

  • If you would like to receive DMARC reports to find out who is sending e-mails with your domain name, as well as examples of e-mails sent with your domain name but failing their SPF or DKIM tests:

    "v=DMARC1; p=none; rua=mailto:[email protected]; ruf=mailto:[email protected]; fo=1;

  • If you want your recipients to receive emails not authenticated by your organization in their spam folder :

    v=DMARC1; p=quarantine; rua=mailto:[email protected];

  • If you don't want your recipients to receive e-mails not authenticated by your organization :

    v=DMARC1; p=reject; rua=mailto:[email protected]

🔍 Check your settings

Once you have (re)connected your email to ZELIQ, you can check if your SPF and DKIM records have been added correctly by clicking on your initials, then "Email Accounts", clicking on your domain's name, and opening the window "DNS Settings".

4️⃣ Keep your sending volume "low" per domain

The volume of emails you send is crucial in determining whether your cold emails end up in spam filters.

To steer clear of spam filters and boost your response rate, it's best to keep your sending volume lower and focus on personalizing each email more. This approach ensures better deliverability and engagement.🦾

💡Control the number of emails you send within ZELIQ by clicking on your initials, then "Email Accounts", clicking on your domain's name, and opening the window "Safety Settings".

We recommend you send between 50 and 60 emails by domain per day.

Also, it's essential to “warm up” your new email addresses. This means gradually sending an increasing number of emails to establish a good reputation.

Warmup plan

- Week 1: Start by sending 5 emails a day.

- Week 2: Increase to 10 emails per day.

- Week 3: Keep increasing until you reach 30 to 40 emails per day.

Warmup tools

You can also use tools like Smartlead or Mailwarm to automate the warmup process and monitor the reputation of your email addresses until ZELIQ adds the feature to the platform. 😉

💚 Best practices to start with cold emailing

For the best sequences example, have a look at our Case Study!

1️⃣ Send the right emails to the right people and personalize them

Having the right prospects is key to ensuring your emails don't get caught in spam filters.

🧐 When you're reaching out, ask yourself:

  • Are these people genuinely interested in what I have to say?

  • Have I done my research to personalize each email?

  • Can I offer them real solutions to their business challenges?

Asking these questions helps ensure you're targeting the right audience and keeping your outreach focused.

By narrowing down your prospect list, you'll have more time to personalize each email, making it more likely to resonate with recipients. Plus, with fewer emails sent, ESPs are less likely to flag your messages as spam.

Use ZELIQ's variables to personalize each email you send with at least their name, company name, and a little detail that shows you've done your homework! 😉

🤓 Variables can also be used in objects by clicking the "+" to the right of the object line.

For example, instead of starting with your pitch, kick things off with something personal. Maybe you noticed they were featured in a podcast, or their company made headlines in the local news.

Simple, right?

2️⃣ Leave Out The Attachment

Even if your sales deck is top-notch, bombarding your prospects with it in your first email isn't the way to go.💥

Plus, spam filters tend to be extra cautious with emails that have attachments and are sent to cold prospects.

To avoid getting lost in the spam folder, it's best to skip attachments initially and focus on starting a conversation and building rapport with your prospect in your first email.

This approach is more likely to lead to responses and positive outcomes from your outreach efforts.🤩

3️⃣ Choose the right words

🔍 Why avoid certain words?

Email providers' spam filters analyze email content to detect terms frequently used in spam emails. Using these words can increase the risk of your e-mails being sent directly to recipients' spam folders.

📝 List of words to avoid

  • Finance: free, 100% free, no charge, credit card, instant loan, discount, save

  • Urgency and Incentives: urgent, immediately, click here, activate now, don't miss, limited offer

  • Marketing and Promotions: promotion, special offer, price, buy now, buy, order, order, discount

  • Earnings and Opportunities: earn money, make money, income, guaranteed return, wealth, double your income

  • Health: weight loss, diet, miracle, cure, magic solution

  • Miscellaneous: sex, casino, gambling, bet, win, luck

⚔️ Examples of replacement

1. Free

- Avoid: “Get your free product now!”

- Replace with: “Discover our exclusive offer at no extra cost.”

2. Click Here

- Avoid: “Click here for more information.”

- Replace with: “Visit our site to learn more.”

3. Urgent

- Avoid: “Urgent action required!”

- Replace with: “Make an informed decision today.”

4️⃣ Verify Email Addresses Before Sending Your Email

Suppose Email Service Providers (ESPs) and spam filters detect a significant number of bounced emails from your account. In that case, this issue will escalate, increasing the likelihood of your emails being flagged by spam filters in the future.🫣

Don't worry, ZELIQ got your back! We verify every email address of your sequence's lead before sending them, to avoid damaging the health of your domain!

There's no guaranteed way to ensure your cold emails steer clear of the spam filter.

Even the most well-crafted cold email campaigns might end up with a few emails finding their way into the spam folder. But, by following these steps, you can start to reduce the likelihood of this happening in your campaigns.🤩

👩🏼‍💻 For further information, please do not hesitate to contact us:


Master the Sales Game by checking our ZELIQ Academy on our Website or through our YouTube Channel 🚀

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