Cold email outreach is a valuable way to connect with people and grow your business. But, there's a big challenge: email security. You want your emails to reach the right people and not get lost in spam folders. To solve this problem, we have three important acronyms: SPF, DMARC, and DKIM. These are like secret agents for your emails, making sure they're safe and sound. In this blog, we'll explain why SPF, DMARC, and DKIM are super important for successful cold email campaigns.

What is DKIM?

DKIM, which stands for DomainKeys Identified Mail, is a security measure for email. Imagine it like a digital signature for your emails. When you send an email, DKIM adds a special signature to it. On the receiving end, the recipient's email system checks this signature to verify that the email genuinely comes from your business and hasn't been tampered with along the way. For small business owners using cold email, DKIM helps in building trust with recipients by ensuring your emails are genuine and increasing the chances of your emails landing in the inbox rather than the spam folder.

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What is SPF?

SPF, which stands for Sender Policy Framework, is like a guest list for your email party. When you set up SPF for your business email, you're basically telling the internet which mail servers are allowed to send emails on behalf of your domain. When a recipient's email system receives a message from your business, it checks the SPF "guest list" to see if the sending server is approved. If the server isn't on the list, the email might be flagged as suspicious or rejected altogether. For small business owners getting into cold email, setting up SPF is crucial. It helps prevent fraudsters from sending emails pretending to be you and ensures your legitimate emails have a better chance of reaching your recipient's inbox without being mistaken for spam.

What is DMARC?

DMARC, which stands for Domain-based Message Authentication, Reporting, and Conformance, is like a security guard for your email. It builds on top of two other email security measures, DKIM and SPF. When someone receives an email from your business, DMARC helps the recipient's email system decide what to do with it. If the email looks suspicious (like if it fails the DKIM or SPF checks), DMARC can advise the receiving system to either block it or send it to the spam folder. For small business owners diving into cold email, DMARC gives you a way to protect your brand by ensuring that only legitimate emails from your business reach the recipient's inbox, and it provides feedback on how your emails are being handled, so you can make sure your messages are being delivered effectively.

What are other factors in cold email deliverability?

Cold email deliverability depends on various factors beyond SPF, DMARC, and DKIM. Here are some key considerations to enhance the chances of your cold emails reaching their intended recipients' inboxes:

Relevance: Ensure that your email content is relevant to the recipient. Personalize your messages by addressing the recipient by name and tailoring your content to their interests or needs.

Sender Reputation: Maintain a good sender reputation by sending high-quality, non-spammy content. Avoid sending emails from domains with a history of spamming, as this can negatively impact your deliverability.

List Quality: Use a clean and well-maintained email list. Remove invalid email addresses, duplicates, and addresses that have bounced in the past. Coldlytics is among the best list sources for cold email in the world.

Email Volume: Gradually increase your email sending volume to avoid triggering spam filters. Sending too many cold emails at once can raise red flags with email service providers.

Engagement Metrics: Monitor open rates, click-through rates, and reply rates. Higher engagement signals to email providers that your emails are valuable and wanted by recipients.

Opt-Out Mechanism: Include a clear and easy-to-use unsubscribe option in your emails to comply with anti-spam regulations. Honoring opt-out requests promptly is essential.

Timing: Send emails at optimal times based on your target audience's time zones and work schedules. Avoid sending emails during weekends or holidays when they are less likely to be seen.

Subject Lines: Craft compelling subject lines that grab recipients' attention without being misleading or spammy. A well-crafted subject line can improve open rates.

Content Quality: Create valuable and informative content that provides a benefit to the recipient. Avoid using excessive capitalization, exclamation marks, or overly promotional language.

Email Testing: Before sending a campaign, test your emails across different email clients and devices to ensure they render correctly. This helps prevent formatting issues that can affect deliverability.

Warm-up Period: If you're using a new domain or email address, start with a "warm-up" period where you gradually increase your sending volume to establish a positive reputation.

Monitoring and Adjusting: Continuously monitor your email campaigns' performance and adjust your strategies based on the feedback and data you gather.

Compliance: Ensure that your cold email campaigns comply with local and international spam laws, such as the CAN-SPAM Act in the United States or GDPR in the European Union.

Considering these factors can help improve the effectiveness of your cold email campaigns and enhance deliverability.

They play a crucial role; SPF, DMARC, and DKIM protocols, in ensuring the successful delivery of cold emails. These protocols work together to enhance email security and authenticity, preventing emails from ending up in spam folders and ensuring they reach the intended recipients' inboxes. Beyond these protocols, there are other factors influencing cold email deliverability, including sender reputation, list quality, engagement metrics, content quality, and compliance with anti-spam laws as mentioned, along with several others.

By considering these factors and implementing best practices, cold email campaigns can be more effective and reliable.

How Do SPF, DKIM, and DMARC Work Together?

When you send a cold email, the receiving server checks:

  • If the sending server is authorized by SPF.
  • If the email's integrity is intact via DKIM.
  • How to handle the email based on DMARC policy if SPF or DKIM checks fail.

Successfully passing these checks significantly boosts your email's credibility, making it more likely to reach the recipient's inbox and not get filtered as spam.

Implementing SPF, DKIM, and DMARC for Better Cold Emailing Results

Implementing these protocols can seem technical, but it's a critical step for anyone serious about cold emailing. Here’s a simplified approach:

  • SPF: Update your domain's DNS settings to include the IP addresses of your email sending servers.
  • DKIM: Generate a DKIM key pair and add the public key to your DNS records. Configure your email sending service to sign emails with the private key.
  • DMARC: Start with a lenient policy to monitor how your emails perform and adjust based on the reports you receive. Publish your DMARC policy in your DNS records.


SPF, DKIM, and DMARC are not just acronyms to gloss over; they're essential parts of your cold email setup. They help authenticate your emails, build trust with email service providers, and ensure your messages reach their intended destination. Implementing these protocols might require some technical setup, but the boost in email deliverability and protection against spoofing and phishing attacks is well worth the effort.

If your emails aren't getting through, then all your effort is wasted. This is a necessary step.


If you're not sure HOW to set this up, use this advanced search query template in Google: 

How to "setup" "SPF" "DKIM" "DMARC" in "[Domain-Provider]"

Quality data for cold email, phone, or direct mail. Researched on demand.

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