Did you know that 1 in 5 emails never makes it to the inbox? For cold emails, it’s even worse - 85% end up in spam folders. If your emails aren’t reaching recipients, you’re losing opportunities and damaging your sender reputation.
Here’s how to fix it:
Quick Tip: A strong sender reputation and proper setup are critical. Start today to improve your email deliverability and ensure your messages land where they belong - in the inbox.
Email authentication protocols are essential for proving your legitimacy to email providers. Without proper setup, your emails are likely to be flagged as spam - or worse, not delivered at all.
The foundation of email authentication rests on three key protocols: SPF, DKIM, and DMARC. Here's how they work:
In February 2024, Google and Yahoo introduced stricter requirements for bulk email senders. If you're sending more than 5,000 emails daily, you must have SPF, DKIM, and a DMARC record for your "From" address domain. Without these, your emails will likely be rejected outright.
To ensure your emails pass authentication checks, follow these steps:
1. Setting Up SPF
SPF (Sender Policy Framework) prevents email spoofing by creating a list of servers and IPs authorized to send emails from your domain.
v=spf1 include:_spf.google.com include:mailgun.org ~all.2. Configuring DKIM
DKIM (DomainKeys Identified Mail) adds a digital signature to your emails, verifying that they haven't been tampered with.
selector1._domainkey.yourdomain.com.3. Implementing DMARC
DMARC (Domain-based Message Authentication, Reporting, and Conformance) works alongside SPF and DKIM to define how email providers should handle messages that fail authentication.
v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; ruf=mailto:dmarc@yourdomain.com; sp=none; aspf=r; adkim=r._dmarc.yourdomain.com.As DMARCLY experts explain:
"A full DMARC implementation prevents your emails from being spoofed and improves email deliverability."
However, they caution:
"Sending emails without monitoring the email authentication status is little more than a shot in the dark."
| Protocol | Purpose | How It Works | Key Benefit |
|---|---|---|---|
| SPF | Verifies the sender's authenticity | Lists authorized IPs and domains in DNS | Protects against email spoofing |
| DKIM | Confirms the email's integrity | Adds a digital signature to the email header | Prevents forgery and tampering |
| DMARC | Defines handling of failed emails | Aligns SPF and DKIM results with the "From" domain | Improves security and email trustworthiness |
Domain alignment ensures consistency across your email headers. For DMARC to work effectively, the domain used in SPF or DKIM must match the "From" domain in your email message. This means your "From" address domain, return-path domain, and DKIM signing domain should align.
You can choose between two alignment modes: strict and relaxed.
sales@company.com, your SPF and DKIM domains must also be company.com.sales@marketing.company.com could align with company.com.For cold email campaigns, strict alignment is often better, as it provides higher security and boosts deliverability. Providers are more likely to trust emails from domains with consistent alignment.
To achieve proper alignment:
The 2024 updates from Gmail and Yahoo have made domain alignment even more critical. Misaligned domains are now under greater scrutiny and are more likely to land in spam folders.
Using shared tracking domains can hurt your email delivery rates. When you rely on default tracking domains provided by email platforms, you share their reputation with countless other senders. If another sender misuses the domain, your deliverability suffers too.
Custom tracking domains solve this problem by giving you control over your link reputation. Instead of links pointing to track.emailprovider.com, they can point to track.yourdomain.com or a similar subdomain you own.
To set up a custom tracking domain:
links.yourdomain.com or track.yourdomain.com).For the best results:
sales@company.com, use a tracking domain like links.company.com.Did you know about 20% of emails never make it past spam filters? That’s a big chunk, and it highlights why optimizing your email content is so important. While technical measures protect your sender reputation, the way you craft your content plays a huge role in staying out of the spam folder.
Spam filters have come a long way. They’re no longer just looking for specific keywords - they now assess sender reputation, how recipients engage with your emails, and the overall quality of your content. That said, certain words and phrases still act as red flags and can harm your email deliverability.
Spam filters flag certain words and phrases that hint at scams, gimmicks, or unethical behavior. While reputable senders using these terms sparingly in well-coded emails are usually fine, overusing them - especially in poorly coded emails - raises your spam risk.
These red-flag terms generally fall into categories like exaggerated claims, urgency tactics, financial offers, and problematic phrases. Instead of avoiding these ideas altogether, you can rephrase them in ways that sound professional and trustworthy. For example:
Here’s a quick breakdown of common triggers and their alternatives:
| Category | Avoid These Words | Use These Alternatives |
|---|---|---|
| Exaggerated Claims | 100% free, guaranteed, miracle, best price | Complimentary, reliable, effective, competitive pricing |
| Urgency Tactics | Act now, urgent, don't delete, winner | Respond by [date], time-sensitive, selected recipient |
| Financial Offers | Free trial, save big money, no cost | Complimentary trial, significant savings, no initial investment |
| Potentially Problematic Phrases | Dear friend, this isn't a scam, no catch | [Recipient's name], transparent offer, straightforward terms |
"Spam filters will help catch low-quality cold emails, leaving room in your prospects' inbox for high-quality, valuable cold emails to come through." - Jeremy Chatelaine, QuickMail
Keep in mind that violating the CAN-SPAM Act can cost you up to $16,000 per email, so compliance is a must. Before hitting send, use spam-check tools to scan your content for potential issues.
Once you’ve refined your language, it’s time to focus on connecting with your audience on a personal level.
Personalization doesn’t just boost engagement - it also signals to email providers that your messages are tailored, not mass-blasted. But personalization isn’t just about plugging in someone’s name. It’s about showing you’ve done your homework.
Look into their LinkedIn activity, recent company milestones, or industry challenges. For example, instead of saying, "I noticed you work in marketing", you could write, "I read your recent article on marketing automation trends in healthcare, and your insights on patient engagement stood out to me."
Personalized emails can deliver impressive results: they generate 26–29% higher open rates and up to 41% higher click-through rates, with a potential $20 return for every $1 spent. Just don’t go overboard - over-personalization can feel invasive or fake.
To make personalization work, segment your audience by factors like industry, company size, or location. Then test different approaches to see what resonates best.
"The goal of personalization is to speak directly to one person, one company, one lead, whichever applies." - Chase
With your personalized message ready, the next step is crafting a call-to-action (CTA) that’s both engaging and spam-safe.
A well-written call-to-action (CTA) is crucial - it’s what drives recipients to take the next step. But if your CTA feels pushy or overly promotional, it can trigger spam filters or even complaints. To avoid this, focus on clarity and value.
"In my opinion, the CTA copy is just as important as what you write for email subject lines. One gets an open, and the other earns the click." - Kasey Steinbrinck, Author, Sinch Email on Acid
Before you write your CTA, think about what you want the recipient to think, feel, and do. This mindset helps you craft CTAs that resonate without coming across as aggressive.
Instead of emphasizing your goals, highlight the recipient’s benefit. For example, replace "Buy now" or "Sign up today" with "Get your personalized analysis" or "Schedule your strategy session." People are more likely to click when they see what’s in it for them.
"People won't click unless they feel there is value in doing so. That means your contacts are always asking, 'What's in it for me?' before they choose to click or tap a CTA." - Andy Crestodina, Digital Marketing Expert
If you want to create urgency, avoid spammy phrases like "limited time" or "act fast." Instead, use specific details like "Reserve your spot for the January 15th workshop" or "Join the next cohort starting February 1st." This approach builds urgency without sounding like a gimmick.
Another tip? Use first-person language that mirrors what the recipient might think. For example, "Show me the demo" or "Send me the case study" feels more natural than "Click here for demo" or "Download case study." It’s less of a command and more of an invitation.
Finally, experiment with different CTA styles. While short and clear CTAs often work best, longer ones that address a specific pain point or highlight a benefit can sometimes perform better. For instance, "Help me reduce our customer acquisition costs" might get more clicks than "Learn more."
Make sure your CTAs are easy to read and not overly aggressive. Stick to sentence case, avoid excessive punctuation, and ensure your links and buttons use HTTPS for better security and trustworthiness.
"Spam filters nowadays are beginning to pay more attention not just to specific spam words as might have been the case previously but also to the overall reputation of the sender and the engagement generated by email recipients." - Yaroslav, Deliverability Expert, Mailtrap
Once you've nailed down authentication and created quality content, the next big piece of the puzzle is your sender reputation. This reputation determines whether your emails reach inboxes or get blocked outright. Major email providers like Gmail, Outlook, and Yahoo closely monitor how recipients interact with your emails, and this data directly impacts your deliverability. A strong sender reputation can make or break your email campaigns.
Did you know that over 20% of legitimate emails never make it to their intended recipients because of blacklists? The good news? There are clear steps you can take to strengthen and safeguard your reputation, starting with cleaning up your email lists. Let’s dive into the details.
Keeping your email list clean is non-negotiable if you want to avoid deliverability issues. On average, mailing lists shrink by 22% annually, with up to 15% of addresses becoming invalid. Cleaning your list means removing unengaged, unsubscribed, invalid, or duplicate contacts. This not only boosts your engagement rates but also ensures compliance with email marketing regulations and helps you avoid unnecessary headaches.
Here’s what to focus on:
As the 2ten Marketing Team explains:
"List cleaning is a fundamental practice for maintaining good deliverability, ensuring your emails land in recipients' inboxes, and creating a healthier, more engaged subscriber base."
Before cutting inactive subscribers, consider running a re-engagement campaign to win them back. And make it a habit to clean your list every 3-6 months.
Once your list is in great shape, it’s time to focus on warming up your email accounts to build credibility.
Launching a new email account and sending out a high volume of emails right away is a recipe for disaster. You’ll likely trigger blocks or land in spam folders. Instead, take the time to warm up your account - a gradual process where you build trust with email providers by slowly increasing your sending volume over 4-5 weeks.
Here’s how to do it:
If you’d rather not handle this manually, tools like Warmforge can automate the process. They’ll adjust your sending volume and monitor your reputation metrics, so you can focus on creating great content.
Google Postmaster Tools back this up: a higher domain reputation means your emails are less likely to be flagged as spam. During the warm-up phase, avoid using spammy phrases like "guaranteed", "get rich", or "cheap" to protect your growing reputation.
Blacklists are essentially databases of IPs and domains flagged for spam-like behavior. If you’re blacklisted, your emails might not even reach your recipients’ spam folders - they’ll be blocked entirely.
To stay ahead of blacklist issues:
If you find yourself blacklisted, take these steps:
Maintaining a strong sender reputation takes consistent effort. By regularly cleaning your lists, carefully warming up your accounts, and staying vigilant about blacklist issues, you’ll be well on your way to ensuring your emails land where they’re supposed to: in your recipients’ inboxes. These steps are the foundation of a successful email deliverability strategy.
Once your sender reputation is secure, the next big step is choosing the right email infrastructure. This setup plays a critical role in whether your cold emails land in inboxes or get flagged as spam. Factors like shared versus private systems, the number of IP addresses, and mailbox location all influence your success. As Yevhenii Odyntsov aptly states:
"If you care about email deliverability, your choice of IP setup matters."
Here’s what you need to consider when building your email infrastructure.
When it comes to email infrastructure, you have two main options: shared or private. Each has its pros and cons, directly affecting your control and deliverability.
Here’s a quick comparison of the two:
| Infrastructure Type | Cost | Setup & Warm-up | Reputation Control | Best For |
|---|---|---|---|---|
| Shared | Budget-friendly (often included in basic plans) | No warm-up needed | Limited control | Small to medium senders, cost-conscious businesses |
| Private | Higher cost | Requires careful warm-up | Full control | High-volume senders, businesses needing reliability |
If your monthly email volume exceeds 100,000, a dedicated IP address is often the smarter choice.
For businesses just starting out, Mailforge offers shared servers with minimal setup time, making it a great budget-friendly option. On the other hand, Infraforge caters to those scaling up, providing private servers with dedicated IPs for maximum control and deliverability.
Using multiple IP addresses can significantly enhance your email campaigns. By spreading your email volume across several IPs, you reduce the risk of spam filters flagging your emails and protect against any one IP being blacklisted.
Here’s why multiple IPs make a difference:
As Rob Pellow, digital experience director at Armadillo, explains:
"An IP reputation is hard to build, easy to lose, and hard to regain. Therefore, ensuring you are sending the best emails before they are sent will limit the damage caused, and monitoring, post-send, will allow fine-tuning - and it will allow you to know when further action needs to be taken to protect or improve your IP status."
To make the most of multiple IPs, ensure you:
Companies like Glassdoor and Shopify have seen the benefits of proper IP management. Glassdoor achieved a 99.5% delivery rate with a spam rate as low as 0.007% by using dedicated IPs. Shopify’s IP pool management led to a 99.5% delivery rate and a 91.3% inbox placement rate.
Infraforge stands out in this area, offering tools to manage multiple IPs effectively, helping you scale campaigns while maintaining control over each IP’s performance.
If your target audience is in the US, using US-based mailboxes can significantly improve your deliverability. The mailbox location influences how email providers perceive and route your messages, especially when paired with localization strategies.
The US email market is massive, with around 9.7 billion emails exchanged daily as of April 2024. The average inbox placement rate in North America is approximately 85%. Using US-based infrastructure can help you compete effectively in this environment.
Why does this matter? US-based Google Workspace and Microsoft 365 mailboxes align with the expectations of domestic email providers. They can also simplify compliance with regulations like the CAN-SPAM Act. Beyond technical advantages, aligning your infrastructure geographically with your audience can boost delivery speeds and reduce filtering risks.
When targeting US audiences, tailoring your messaging is crucial. Statistics show that 47% of recipients decide to open an email based on the subject line alone, and 72% engage only with content that feels relevant to their interests. This means referencing US-specific holidays, using familiar examples, or showcasing local success stories can make a big difference.
Timing also plays a role. Since 50% of the US population is in the Eastern Time Zone, scheduling emails around this time zone can maximize engagement.
Primeforge offers US-based Google Workspace and Microsoft 365 mailboxes with US IP addresses, ensuring your infrastructure aligns with your audience’s location and expectations.
Your email infrastructure decisions - whether shared or private, single or multiple IPs, or local versus international mailboxes - will shape your deliverability success. Tailor your choices to your volume, budget, and audience for the best results.
Once your email infrastructure is up and running, the next step is to ensure it operates smoothly. Regular testing and monitoring are essential to spot and resolve deliverability issues before they impact your campaigns.
Inbox placement tests help you determine where your emails land - whether that’s the primary inbox, spam folder, promotions tab, or another folder across various email clients and ISPs.
Using an inbox placement tool, you can send test emails and review detailed reports that highlight potential deliverability issues. These tools provide insights into where your emails are being delivered and offer feedback by mailbox provider and folder placement.
"With inbox placement testing you can proactively test where your emails will land at major mailbox providers before you send." – Mailgun
Warmforge stands out in this area, combining inbox placement testing with email warming services. This dual approach helps your emails bypass spam filters and strengthens your sender reputation for consistent deliverability.
It’s a good idea to test before major campaigns, after making changes to your email template or authentication settings, and on a monthly basis to catch any gradual shifts. Use the test results to make adjustments and re-test to confirm that the issues have been resolved.
Bounce and complaint rates are key indicators of your email campaign’s health. They alert you to problems early, so you can take action before they escalate.
To maintain a strong sender reputation, aim for bounce rates below 2% and spam complaints under 0.1%. You can achieve this by implementing double opt-in methods, promptly removing hard bounces, and providing clear unsubscribe options.
| Metric | Good Benchmark | How to Improve |
|---|---|---|
| Bounce Rate | Below 2% | Use double opt-in, remove hard bounces immediately, and monitor list quality |
| Spam Complaint Rate | Below 0.1% | Provide clear unsubscribe options, segment lists, and use relevant content |
| Unsubscribe Rate | Below 0.5% | Maintain consistent frequency, allow preference customization, and segment audiences |
Set up alerts for spikes in bounce or complaint rates. Remove hard-bounce addresses immediately to protect your reputation. For soft bounces, allow a few retries before removing them from your list.
Once you’ve established baseline performance metrics, use A/B testing to refine your emails. By testing one element at a time, you can identify what drives better results.
To ensure reliable results, use sufficiently large sample sizes and send test emails to comparable groups simultaneously.
A great example of strategic testing comes from Fast Growing Trees, which compared SMS and MMS campaigns. They found that SMS achieved 10 times the expected click rate at a third of the cost, leading to a 231.7% quarter-over-quarter growth in SMS click rates.
"Email marketing A/B testing has so many benefits, such as solving user problems and improving UX, driving growth and business impact, optimizing content for diverse audience segments as well as gaining insight and learnings you can apply to future campaigns." – Rob Gaer, Senior Software Engineer at Miro
Analyze your test results to pinpoint the winning elements and understand why they performed better. Use these insights to guide future campaigns and continuously improve your email performance.
Focus your efforts on emails that generate revenue or are critical to your goals but easy to tweak. Start with a clear hypothesis about why a particular variation might work better, and prioritize tests that offer impactful results with minimal effort.
To ensure your cold emails avoid the dreaded spam folder, stick to these essential practices.
First, set up SPF, DKIM, and DMARC in your DNS settings. Marcel Becker, Senior Director of Product at Yahoo, emphasizes their importance:
"All of these requirements have been well documented best practices for years. A lot of senders have already implemented them. Authenticating your email traffic should be something that you're already doing if you care about the health of your email traffic as well as your infrastructure."
Next, focus on crafting better email content. Avoid spam trigger words, personalize your messages, and include clear, concise calls-to-action. It’s worth noting that 70% of emails contain at least one issue that could land them in spam.
Keep your email lists clean and gradually warm up new accounts. A strong sender reputation is critical, especially since 1 in 5 emails fails to reach the inbox due to poor engagement or reputation problems. Building trust with email providers is a long-term effort that pays off in better deliverability.
Invest in a reliable email infrastructure. With only 1 out of 40 cold emails successfully avoiding spam, having a solid setup is non-negotiable. Tools like Mailforge offer shared cold email infrastructure with automated DNS configuration and premium deliverability features. For advanced users, Infraforge provides private infrastructure with dedicated IPs for greater control and performance.
Lastly, continuously monitor and refine your campaigns. Regular inbox placement tests, tracking bounces and complaints, and running A/B tests on email elements can help you fine-tune your strategy and safeguard your sender reputation.
SPF, DKIM, and DMARC are three critical email authentication protocols that work together to ensure your emails land in inboxes rather than being flagged as spam. Here's a closer look at how each one functions:
Together, these protocols not only safeguard your domain from misuse but also boost your email deliverability, ensuring your messages reach your audience's inboxes with greater reliability.
To make your cold emails stand out and avoid being flagged as spam, focus on making them feel personal and meaningful. Start by addressing the recipient by name and referencing specific details about them, such as their company, job title, or recent accomplishments. This small effort can make your email feel more genuine and engaging.
Be mindful of avoiding spam trigger words like "free" or "guaranteed", and steer clear of overusing punctuation marks, as these can raise red flags with spam filters. On the technical side, ensure you’re using proper email authentication protocols like SPF, DKIM, and DMARC to protect your sender reputation. Finally, prioritize offering real value in your message. Emails that are relevant and helpful to the recipient are far less likely to land in the spam folder.
If your domain or IP address ends up on a blacklist, the first step is to confirm its status by running a blacklist check. Once confirmed, dig into the root cause. Common culprits include sending spam, high complaint rates, or misconfigured email settings. To fix the issue, start by correcting your DNS records, ensuring proper email authentication (like SPF and DKIM), and scanning for malware. After addressing these problems, follow the delisting process outlined by the blacklist service, which often involves submitting a formal removal request.
To avoid blacklisting in the future, focus on maintaining a strong sender reputation. Stick to emailing only those who have opted in, regularly clean up your email list, and steer clear of spammy content. On the security side, use strong passwords, enable SMTP authentication, and keep an eye on your sending practices to prevent your domain from being compromised. By staying proactive with these measures, you’ll improve deliverability and protect your email reputation.