Email Marketing Outbound

14 Cold Email Deliverability Tactics for 2024: Outsmarting Spam Filters and Boosting Reach

This guide explores 14 essential tactics for improving cold email deliverability in 2024, focusing on outsmarting spam filters through domain management, authentication, content optimization, and ongoing monitoring.

In the world of cold emailing, your fiercest adversaries aren’t your competitors—they’re the spam filters. Designed by email providers like Gmail, Outlook, and others, these filters are gatekeepers, constantly evolving to weed out irrelevant, unsolicited, or suspicious messages. Cold email success doesn’t just rely on crafting the perfect pitch; it starts with getting your email into the inbox.

Below, we’ll delve into 14 of the most effective tactics to outsmart spam filters in 2024. These are the strategies email service providers don’t want you to know. We’ll explore everything from domain and inbox configurations to advanced content optimization and testing techniques. Each tip comes with actionable, high-quality advice to boost deliverability without cutting corners.

Category 1: Domain and Inbox Setup

A strong deliverability strategy begins with how you configure your domain and inboxes. This is the foundation that email service providers scrutinize, determining whether your cold emails even have a chance to be seen.

1. Rotate Multiple Domains and Inboxes Strategically

Why It Matters:

Spam filters constantly track the volume of emails being sent from a single domain or inbox. If you send too many cold emails from one domain, you’ll eventually get flagged, even if the emails are well-crafted. Multiple domains and inboxes allow you to distribute your sending volume across different channels, reducing the risk of blacklisting.

How to Do It:

  • Start with 2-4 domains: Choose domains that relate to your brand but don’t use gimmicky variants. For example, avoid things like “bestdeals-yourcompany.biz” and go for subtle variations like “getyourbrand.com” or “trybrandnow.com.”
  • For each domain, set up 3-5 inboxes. Rotate these inboxes in daily cycles to avoid triggering volume thresholds on any one inbox.
  • Use tools like Folderly to manage inbox health, ensuring that domain reputation issues are detected early and managed effectively.

Advanced Tip: Don’t just rotate randomly. Track which inboxes are performing best using deliverability tools like MailReach or Warmbox.ai and prioritize those inboxes. Some inboxes will naturally build better reputations than others based on audience interactions.

2. Buy Domains from Reputable Providers and Diversify TLDs

Why It Matters:

Domain reputation plays a crucial role in how email filters classify your message. A domain from a cheap or unknown provider can be associated with spammy behavior, leading to immediate deliverability issues.

How to Do It:

  • Stick to reputable providers like Google Domains, Cloudflare, or NameSilo. These platforms offer superior infrastructure and DNS management tools.
  • Avoid only using .com domains. Diversify into .ai, .co, or .io, which are increasingly trusted, especially in the B2B tech space.
  • Avoid subpar domain providers (like certain budget options), as they may lack essential services like DNSSEC or domain privacy, which can lead to increased scrutiny from spam filters.

Advanced Tip: Use Domain Ageing Tools to buy domains that have been around for a while. Newly registered domains can trigger spam filters, but if you acquire an older domain with a clean reputation, your emails are more likely to land in the inbox.

3. Warm Up Your Inboxes Using Advanced Tools

Why It Matters:

Sending a high volume of cold emails from a new inbox without warming it up first is a sure way to get blacklisted. Inbox warming builds credibility with email service providers by gradually increasing your send volume, making your behavior appear more natural.

How to Do It:

  • Use Mailshake Warm-Up, Lemwarm, or Warmup Inbox to simulate natural email interactions. These services send low-volume emails to verified accounts that will respond, mimicking human behavior.
  • Warm your inboxes for at least 4 weeks. Begin by sending 5-10 emails/day for the first week, increasing by 5-10 each day until you reach around 40-50/day. Gradual, organic increases reduce the risk of being flagged.
  • Focus on engagement metrics during the warm-up. The key to successful inbox warming isn’t just the volume of emails sent, but the number of emails opened and replied to.

Advanced Tip: Set up a customized warm-up strategy. Tools like Warmy.io allow you to create custom warm-up templates. Create variations in email content, spacing of emails, and reply structures to mimic natural communication. This provides a more human-like warm-up process, which will improve inbox trust faster.

Category 2: Technical Authentication and Configuration

Even if your emails are crafted perfectly, poor technical configurations will land you in the spam folder. Here’s how to ensure your cold emails pass the most critical spam filters.

4. Set Up SPF, DKIM, and DMARC Correctly (And Review Them Regularly)

Why It Matters:

SPF, DKIM, and DMARC are authentication protocols that verify you are who you say you are. Without these records in place, your emails will likely be marked as spoofed or malicious, preventing them from ever reaching your recipient.

How to Do It:

  • SPF (Sender Policy Framework): Set up a record that lists all the IPs allowed to send emails from your domain. Use an SPF generator tool (like MxToolbox) to ensure it’s correctly configured.
  • DKIM (DomainKeys Identified Mail): Sign your emails with a unique key. Use your email provider’s DKIM setup guide (e.g., Google Workspace has a straightforward setup).
  • DMARC (Domain-based Message Authentication): Set a policy to instruct email providers what to do if an email fails SPF or DKIM checks. Monitor DMARC reports regularly using tools like Postmark or Dmarcian.

Advanced Tip: Use a DMARC report analyzer like EasyDMARC. These services automatically interpret DMARC data, allowing you to spot problems in your email authentication that you might otherwise miss.

5. Configure a Custom Tracking Domain to Track Opens and Clicks

Why It Matters:

Shared tracking domains (provided by platforms like Mailchimp or Hubspot) are often abused by other users and can be blacklisted. A custom tracking domain ensures that your links and tracking pixels don’t get caught up in spam filters.

How to Do It:

  • Register a separate tracking domain (e.g., “track.yourcompany.com”) to handle email metrics.
  • Set up a CNAME record to point to your email service provider’s servers, allowing for accurate tracking of opens and clicks without relying on shared resources.

Advanced Tip: Tools like SparkPost offer real-time analytics and allow you to integrate with custom tracking domains seamlessly. Make sure to choose a platform that supports granular tracking for better insight into recipient behavior.

Category 3: Crafting Content That Avoids Spam Triggers

Spam filters analyze not just the technical setup but also the content of your emails. Certain phrases, structures, and formats can raise red flags, no matter how legitimate your offer is.

6. Avoid Common Spam Trigger Words and Overly Promotional Phrases

Why It Matters:

Content analysis algorithms detect specific words or phrases that are commonly associated with spam. Overly promotional language can send your emails directly to the junk folder, even if the rest of your setup is flawless.

How to Do It:

  • Avoid using classic trigger words like “Buy now,” “Free trial,” or “Limited time offer.” Instead, focus on value-driven language that explains the benefit without sounding like an advertisement.
  • Use tools like SpamAssassin to scan your emails for suspicious phrases.
  • A/B test subject lines and avoid generic calls-to-action. Instead of “Act Now,” try something like “Let’s discuss [benefit].”

Advanced Tip: Use natural language processing (NLP) tools like Grammarly’s Tone Detector or Hemingway Editor to ensure your tone isn’t too aggressive or promotional. Keeping your email tone conversational and informative will pass more spam filters.

Why It Matters:

Emails overloaded with links often get flagged as spam. The more links you include, the higher the likelihood that a spam filter will assume you’re sending a promotional blast.

How to Do It:

  • Limit your email to one essential link, ideally a link to your website or LinkedIn page. Avoid unnecessary links to multiple landing pages or external resources.
  • Avoid using URL shorteners like Bit.ly or TinyURL. These are commonly associated with phishing scams and can hurt your deliverability. Always use full URLs or custom short links from your domain.

Advanced Tip: If you absolutely need to include more than one link (for instance, if you’re offering multiple options), use unique subdomains for each link. For example, you might use “signup.yourcompany.com” for one link and “learn.yourcompany.com” for another, instead of directing all traffic to the same domain.

Category 4: Continuous Monitoring and Deliverability Testing

No matter how well you set up your campaign, email deliverability is a constantly shifting landscape. Regular monitoring is essential to ensure that your cold emails continue reaching inboxes over time.

8. Regularly Check Blacklist Status and Reputation Scores

Why It Matters:

Email blacklists are databases that identify domains and IP addresses associated with spam. If your IP or domain ends up on one of these lists,

your emails will automatically be marked as spam by most email providers.

How to Do It:

  • Use MxToolbox or GlockApps to check whether your domain or IP is on any blacklists.
  • Integrate blacklist monitoring tools like ZeroBounce or SendForensics into your workflow to receive alerts if your reputation takes a hit.

Advanced Tip: If you discover your domain has been blacklisted, act quickly. Reach out to the specific blacklist service and follow their steps for removal. Some tools, like CleanTalk, offer automated blacklist removal services, allowing you to recover faster.

9. Conduct Seed Testing with a Realistic Inbox Setup

Why It Matters:

Seed testing involves sending test emails to dummy inboxes set up on multiple providers (Gmail, Outlook, Yahoo, etc.) to see where your emails land (inbox, promotions, or spam). This helps you spot issues before they affect your entire campaign.

How to Do It:

  • Use services like GlockApps or MailGenius to perform seed testing.
  • Test from multiple IP addresses to ensure consistency in your results. Some email service providers will treat the same email differently based on where it’s coming from.

Advanced Tip: Pair seed testing with real-world user feedback. Ask a few trusted contacts to check their spam folders for your test emails. This gives you insights that seed testing might miss, as real users often have different filtering behaviors.

Conclusion

In 2024, email deliverability isn’t a one-time task—it’s a dynamic process that requires constant fine-tuning. By using multiple domains, properly configuring authentication protocols, carefully crafting your email content, and continuously monitoring performance, you can outmaneuver even the toughest spam filters.

With the right tools and strategies in place, your cold email campaigns will avoid the spam trap and land squarely in the inbox, where they belong.