Field Guide: Cold Email Deliverability

Email deliverability ensures your carefully crafted emails get to the people you’re trying to reach. It’s all about whether your email ends up in someone’s inbox or gets stuck in a spam filter. Your sending reputation plays a significant role in this.

So, what makes a good email campaign? What keeps your emails from disappearing into the internet abyss?

This guide will break down the nuts and bolts of email deliverability. We’ll cover the basics you need to know and some advanced tips to improve your email game.

Think of this as an internal playbook we’ve put together for our team.

Table Stakes: The Non-Negotiables

There are some foundational elements of email deliverability you can’t afford to overlook. These are your MUST-HAVEs:


These acronyms might seem like alphabet soup, but they’re crucial for your email’s journey to the inbox. They act as your email’s passport, verifying its authenticity and helping it clear customs. 

  • DKIM (DomainKeys Identified Mail): This cryptographic technique allows the receiver to check that the domain sent an email it claims to come from and hasn’t been modified during transit.
  • SPF (Sender Policy Framework): This verifies that the domain’s administrators authorize the sending IP address.
  • DMARC (Domain-based Message Authentication, Reporting, and Conformance): This builds upon DKIM and SPF by specifying a policy for what to do if neither is present or fails to verify.

If these terms are new to you, consider this your wake-up call to get acquainted.

2- Domain Warming: 

Imagine walking into a party and yelling at everyone to listen to you. That’s what blasting emails from a new domain is like. 

  • IP Reputation: Sending from a new domain without warming up can harm your IP reputation, affecting deliverability.
  • Volume Throttling: Gradually increase your sending volume to avoid sudden spikes that could trigger spam filters.

Instead, introduce yourself using a domain warming tool, gradually increasing your sending volume. It’s like building rapport but for your email domain.

3- Email Traffic Control: 

Sending too many emails too quickly can raise red flags. Think of it as a speed limit for your email campaign. 

  • Rate Limiting: ISPs often have rate limits, restricting the number of emails sent in a given time frame.
  • SMTP Queues: Utilize Simple Mail Transfer Protocol (SMTP) queues to manage and pace your outgoing emails.

Keeping the number of emails sent per account low, ideally between 30-100 daily, ensures you’re not labeled a spammer.

4- List Cleaning: 

A clean list is like a well-tended garden; it yields better results. 

  • Hard & Soft Bounces: Identify and remove email addresses that result in hard bounces (permanent failure) and soft bounces (temporary loss).
  • Spam Trap Identification: Detect and remove spam traps that could severely affect your sender reputation.

Tools like ZeroBounce and Hunter act as your garden shears, trimming away the dead ends like bounces, likely complainers, and spam traps. 

This keeps your list healthy and responsive.

Metrics to Watch For: The Numbers That Matter

Metrics are the compass that guides your email campaign. Understanding the right ones can be the difference between a campaign that soars and sinks. 

Here are the key numbers you should keep an eye on:

  • Open Rates: Think of this as your first impression. Aiming for an open rate above 40% is like nailing the introduction at a networking event. Anything less might mean your subject lines or targeting need a second look. It’s your cue to revisit and revise.
  • Bounce Rates: This is your wake-up call. Keeping bounce rates below 5% is crucial. High bounce rates are like a smoke alarm, signaling that your list needs immediate cleaning. Ignore it, and you risk damaging your sending reputation.
  • Reply Rates: This is where the conversation starts. Striving for a reply rate between 5-10% indicates that your message is not just being heard but is also sparking interest. It’s a sign that your messaging is resonating with your audience.
  • Meeting Booked Rate: This is your conversion metric. Aiming for a rate between 0.5% – 1% is a strong indicator that your emails are not just landing but also compelling enough to drive action. It’s a measure of both deliverability and the effectiveness of your overall outreach.

Prospect to booked meeting ratio: This is your big-picture metric. The number of prospects you reach to book a meeting encapsulates the overall effectiveness of your email strategy. It’s like your campaign’s GPA, summarizing its overall performance.

A Deep Dive into Email Deliverability

Sending reputation is like your credit score in the world of email marketing. It’s a composite of various factors that email service providers, like Google and Microsoft, use to determine whether your emails are worthy of the inbox or destined for the spam folder. 

Let’s dissect these components:

  • Content Engagement: 

Apart from having SPF, DKIM, and DMARC set up, email content engagement is essential for your email deliverability. Engagement metrics (like the ones shown below) are vital indicators of your email’s performance.

  • Open Rates: Subject lines and preview text are crucial in enticing recipients to open your email.
  • Click-Through Rates (CTR): The quality and relevance of your links, CTAs, and embedded content directly impact this metric.
  • User Interactions: Actions like forwarding your email or marking it as “important” can positively influence your sender reputation.

Spam Complaints: High spam complaint rates can tarnish your reputation and affect deliverability.

Engaging content serves your immediate goals and contributes to a healthy sending reputation.

  • IP Address Reputation: 

Think of your IP address as your home address in the digital world. Just as you wouldn’t want to live in a bad neighborhood, you wouldn’t want your emails sent from an IP with a poor reputation. 

IPs with a good reputation act like a VIP pass, making your emails less likely to be blocked.

  • Domain Reputation: 

Your domain name is like your family name; it carries weight. Stick with reputable domains that are known for good email practices. A good domain reputation is like having a solid personal brand; it opens doors.

  • Account Reputation: 

This is your track record. Individual email accounts can build their reputations separate from their associated domain. It’s like your personal performance report in a team project; it matters and can affect the overall outcome.

  • Content Factors: 

This is the substance of your email. Spammy content, incorrect links, and inappropriate images are red flags at border control. They can get your email detained in spam filters if recipients mark it as spam.

How to Improve Deliverability

Improving your email deliverability isn’t a one-time task; it’s an ongoing process. Here are some actionable steps to keep you on the right track:

  • Make sure your email campaigns are getting good engagement.

If people find your emails useful and helpful, Google and other providers will take note, improving your reputation and deliverability.

  • Relevance: Tailor your content to your audience’s needs and pain points. The more relevant the content, the higher the engagement.
  • Interactive Elements: Incorporate clickable buttons, polls, or quick links to encourage interaction.
  • A/B Testing: Experiment with different subject lines, content formats, and CTAs to identify what resonates most with your audience.
  • Time Optimization: Send your emails when your audience is most likely to engage, based on analytics.
  • Use reputable providers like Gmail or Office 365.

Think of these providers as your email’s vehicle. A reliable car is less likely to break down, just as a reputable provider is less likely to get your emails flagged.

  • Keep your sending volume reasonable.

This is about pacing yourself. Sending too many emails too quickly can trigger spam filters, akin to a car speeding on a highway attracting police attention.

  • Distribute volume across multiple accounts.

Don’t put all your eggs in one basket. Spreading your email volume across multiple accounts is like diversifying your investment portfolio; it reduces risk.

  • Clean your email lists regularly.

Regular cleaning is as essential for your email lists as for your home. It removes the clutter and ensures you’re only engaging with interested parties.

  • Warm up new accounts and IPs before sending marketing emails.

This is your onboarding process. Just as you wouldn’t run a marathon without training, don’t start a major email campaign without warming up your accounts and IPs.

  • Monitor spam complaints and bounces and remove wrong addresses.

This is your feedback loop. Keep an eye on these metrics, as they can offer real-time insights into your campaign’s health.

  • Follow best practices for email content to avoid red flags.

Content is king, but the wrong kind can dethrone your campaign. Stick to best practices to ensure your emails resonate with your audience.


Mastering cold email deliverability is an ongoing process requiring foundational knowledge and advanced tactics. Every detail counts, from establishing essential authentication protocols to monitoring key performance metrics.

Your emails are more than just messages; they’re opportunities. By following the guidelines outlined in this guide, you can ensure those opportunities don’t go to waste.

Keep this guide handy, stay updated on industry best practices, and continuously optimize your strategy for maximum impact.