Expert Tips to Improve Cold Email Deliverability for Growth Teams

Introduction to Modern Email Deliverability

For growth teams, the success of an outbound campaign is often measured by open rates and conversions. However, there is a silent killer that often goes unnoticed until it is too late: email deliverability. Simply put, if your emails do not reach the inbox, your copy, offer, and targeting are irrelevant.

In the current landscape of digital communication, ISPs (Internet Service Providers) and email service providers like Google and Outlook have implemented sophisticated filters to protect users from spam. For growth-focused organizations, this means that the technical 'plumbing' of an email setup is just as important as the sales strategy. This guide explores the deep technical and strategic shifts required to ensure your cold outreach consistently lands in the primary tab.

To bridge the gap between sending and arriving, many teams turn to specialized solutions. For instance, EmaReach helps growth teams stop landing in spam by combining AI-written cold outreach with automated inbox warm-up and multi-account sending, ensuring emails land in the primary tab where they get noticed.

The Technical Foundation: Authentication Protocols

Before sending a single email, your technical infrastructure must prove to the receiving server that you are who you say you are. Without proper authentication, your emails are likely to be flagged as 'suspicious' or 'spoofed.'

SPF (Sender Policy Framework)

SPF is a DNS record that lists the IP addresses and domains authorized to send emails on behalf of your domain. When an email is received, the recipient server checks the SPF record. If the sender isn't on the list, the email is often rejected or sent to spam.

DKIM (DomainKeys Identified Mail)

DKIM adds a digital signature to your emails. This signature ensures that the content of the email has not been tampered with during transit. It acts as a seal of authenticity that gives ISPs confidence in your sender reputation.

DMARC (Domain-based Message Authentication, Reporting, and Conformance)

DMARC is the policy layer that sits on top of SPF and DKIM. It tells the receiving server what to do if an email fails authentication (e.g., 'none', 'quarantine', or 'reject'). Setting up DMARC with a 'quarantine' or 'reject' policy is a strong signal to ISPs that you take security seriously.

Tracking Domain Customization

Most email platforms use a generic tracking domain for open and click tracking. Because thousands of other users share this domain, if one person sends spam, the reputation of that domain suffers, affecting everyone. By setting up a Custom Tracking Domain, you isolate your reputation from other senders, significantly boosting deliverability.

Domain Infrastructure Strategy

Growth teams often make the mistake of sending high volumes of cold emails from their primary company domain (e.g., company.com). This is a high-risk strategy. If your primary domain gets blacklisted, your internal communications, calendar invites, and client updates will all fail.

The Use of Secondary Domains

Smart growth teams purchase 'look-alike' domains specifically for outreach. For example, if your main domain is acme.com, you might use getacme.com or acmehq.com. This creates a 'firewall' around your primary brand reputation.

Inbox Rotation and Scaling

Instead of sending 500 emails a day from one account, it is much safer to send 50 emails a day from 10 different accounts across multiple domains. This distribution prevents any single account from hitting the 'rate limits' set by providers like Google Workspace or Microsoft 365.

Proper Domain Aging

New domains are inherently untrustworthy to ISPs. A domain should be 'aged' or 'warmed' for at least 4 to 8 weeks before being used for high-volume outreach. This involves a gradual increase in sending volume and maintaining a high engagement rate during the initial phase.

The Role of Email Warm-up

Email warm-up is the process of building a positive reputation for a new or underused email account. The goal is to simulate human-to-human interaction to show ISPs that you are a legitimate communicator.

How Automated Warm-up Works

Automated warm-up tools send emails from your account to a network of other 'warm-up' accounts. These accounts automatically open the emails, mark them as 'not spam' if they land in the junk folder, and reply to them. This high engagement rate tells the ISP algorithm that your content is valuable and should be placed in the primary inbox.

Maintaining Consistent Volume

Spikes in email activity are a major red flag for spam filters. If you send 0 emails on Monday and 1,000 on Tuesday, you will likely be flagged. Warm-up tools help maintain a steady baseline of activity, even on days when you aren't running active campaigns.

Crafting Deliverability-Friendly Content

While technical setup is the foundation, the actual content of your email still plays a role in whether you pass the 'content filters' of modern ISPs.

Avoiding 'Spam Trigger' Words

Certain words and phrases are heavily associated with promotional or malicious content. Words like 'Free', 'Buy Now', 'Guarantee', 'Investment', and excessive use of dollar signs can trigger filters. The key is to write like a person, not a marketer.

The Link-to-Text Ratio

An email filled with links and images looks like a newsletter or a marketing blast. For cold outreach, the goal is to look like a one-to-one personal message. Limit your emails to one or two links at most, and avoid using heavy images or attachments in the first touchpoint.

Personalization and Uniqueness

Spam filters look for 'bulk patterns'—thousands of identical emails sent at once. Using 'Spintax' (rotating different variations of words or phrases) and deep personalization (mentioning a specific recent achievement of the prospect) ensures that every email you send is technically unique.

List Hygiene and Data Quality

You can have the best technical setup in the world, but if your lead list is full of 'dead' or 'invalid' emails, your deliverability will plummet.

The Danger of High Bounce Rates

A bounce happens when an email cannot be delivered. A 'Hard Bounce' (invalid email address) is particularly damaging. If your hard bounce rate exceeds 2-3%, ISPs will view you as a low-quality sender who is guessing email addresses or using old, purchased lists.

Verification Tools

Before importing any list into your sending tool, run it through a verification service. These services check if the email address actually exists and if the domain is capable of receiving mail without actually sending an email. This simple step can save your sender reputation from permanent damage.

Identifying Catch-all and Role-based Emails

Catch-all: These domains are set up to receive all emails, even if the specific address doesn't exist. They are risky because they might still bounce later.
Role-based: Addresses like info@, sales@, or admin@ often go to multiple people or are monitored by filters. They rarely lead to high-quality engagement.

Monitoring and Maintenance

Deliverability is not a 'set it and forget it' task. It requires constant monitoring to ensure that your setup remains healthy over time.

Tracking Sender Score and Reputation

Tools like Google Postmaster Tools provide direct insights into how Google views your domain. Monitoring your 'Spam Complaint Rate' is crucial. Even a small number of prospects clicking 'Report Spam' can have a devastating effect on your future campaigns.

Reviewing Engagement Metrics

Open Rates: If your open rate drops below 30%, it is a sign you might be landing in the 'Promotions' tab or 'Spam' folder.
Reply Rates: High reply rates are the ultimate signal of quality. Encourage replies by asking simple, low-friction questions.
Unsubscribe Rate: A high unsubscribe rate is better than a high spam report rate, but it still indicates that your targeting might be off.

Periodic DNS Audits

DNS records can sometimes be accidentally changed or deleted during website updates. Set a recurring task for your growth team to audit SPF, DKIM, and DMARC records once a quarter to ensure they are still correctly configured.

Advanced Strategies for High-Growth Teams

As you scale, you may need to move beyond the basics to maintain high performance across hundreds of daily sends.

Segmenting by ESP

Some teams find that their deliverability varies depending on the recipient's provider. If you find your emails are landing in spam for Outlook users but not Google users, you may need to adjust your sending infrastructure specifically for Microsoft domains.

Using Plain Text Over HTML

While HTML allows for beautiful formatting, plain text emails have a much higher 'human' feel and often bypass filters that are skeptical of complex code. For cold outreach, a simple, text-based approach is almost always superior.

The Power of Multi-Account Sending

Modern outreach platforms allow you to connect dozens of sender accounts. By cycling through these accounts, you mimic the behavior of a large, distributed team rather than a single bot. This 'load balancing' is essential for growth teams aiming to reach thousands of prospects per month without sacrificing the health of their domains.

Conclusion

Improving cold email deliverability is a multi-faceted challenge that requires a blend of technical precision, strategic planning, and ongoing maintenance. By focusing on strong authentication (SPF, DKIM, DMARC), protecting your primary domain through secondary 'sender' domains, utilizing automated warm-up processes, and maintaining impeccable list hygiene, your growth team can ensure that your messages actually reach the people you intend to help.

In an era where digital noise is at an all-time high, the teams that master the art of the 'inbox arrival' are the ones that will ultimately win. Treat your sender reputation as your most valuable asset, and it will reward you with the engagement and growth your business deserves.