8 Proven Strategies to Improve Email Deliverability Today

Improve email deliverability

No other marketing channel produces an ROI quite like email. Statistically, it’s a 36:1 return – which means for every $1 you put into your email program, you can expect $36 worth of benefits.

That’s all well and good so long as your emails actually hit the inbox (duh, right?).

And if they don’t? What’s all the trouble worth anyway?

Well, it’s your lucky day.

At Campaign Refinery, we’ve identified a ton of easy ways to improve email deliverability no matter what skill level you’re currently at — allowing you to maximize those returns to the fullest extent possible every time you click send.

In this post, we will delve into different strategies that can significantly improve your email deliverability based on proven strategies that have 2x-4x our average customers’ opens and clicks… generating millions in additional revenue with no other changes to their marketing.

Pretty exciting, right?

If you follow this guide, we’ll bet our bottom dollar your results show signs of improvement very quickly.

We’ll begin by discussing the significance of warming up new IP addresses and establishing trust with Internet Service Providers (ISPs). Next, we’ll explore how monitoring sender reputation scores can impact your overall deliverability rate. We’ll also cover how list segmentation based on user behavior is critically important both in increasing engagement and reducing unsubscribe/complaint rates.

Then, we’ll touch upon content quality upgrades through subject line testing and proven copywriting techniques. Implementing authentication protocols such as SPF and DKIM will be discussed, along with the benefits they provide for improving email deliverability. The double opt-in subscription process will be highlighted as an essential method for preventing spam trap-related issues.

Lastly, graymail suppression techniques will be examined to showcase their role in enhancing overall deliverability performance. We’ll conclude with best practices for regularly reviewing contact lists to maintain high open rates and click-throughs while keeping databases clean of outdated information.

Table Of Contents:

How to Improve Email Deliverability

Embers warming up

1. Warm Up New IP Address

First, let’s get this big one out of the way.

So many people think their email deliverability issues come from their IP address and they “just need a new IP,” and magically, all of their problems will evaporate like the water reservoirs of Califonia in August.

Unfortunately, it’s just not that simple.

You see, the reputation of an IP is simply a reflection of the domain reputation of the senders who are using that IP. If you have a lot of “HIGH” reputation domains sending on an IP, the IP reputation will go up over time.

If you’re having email deliverability issues, it’s often a domain reputation thing, not something that is purely isolated to an IP.

The second disqualifier you should know is that MOST senders don’t actually need a dedicated IP.

In fact, if you are not sending enough volume consistently, you may have even more email deliverability issues on a dedicated IP than you would on a well-managed shared IP that has other high-quality senders who keep the volume in the sweet spot.

An ideal candidate for a dedicated IP is someone who both:

  • Intends to send 1 million+ email messages per month or more,
  • AND wants to completely isolate their sender reputation from any other senders.

Historically, many email platforms would tell you to start warming up your IP with 100 emails on day 1, and double that volume every day for a new IP. So that would be 100, 200, 400, 800, etc.

The problem with this approach is it doesn’t take into account the current reality and trustworthiness you’re establishing with the ISPs (more on that next). So a much safer and more sustainable approach is to have a much flatter warm-up ramp for your new IP.

We like to send +100 emails from the day before for the first week and increase +250 per day for the following week.

If you’d like an exploded table of what this precisely looks like, we suggest you grab our free Inbox Formula, which has a very handy table that covers this exact warm-up ramp schedule.

Closely following a conservative warm-up ramp for new IPs is critical if your goal is to have a dedicated IP (or a dedicated pool of IPs) before simply dropping in a huge list of subscribers and yelling, “fire in the hole!”. Sending too many emails too quickly when warming up an IP is a quick way to get your emails throttled, blocked, or even trash the reputation of your new IP before you ever even really get started.

We advise that you focus this warm-up on your most engaged, highest quality subscribers as well because this will set the precedent for how well your content is received and what the ISPs think of you going forward, which will continually improve your email deliverability for future sends.

2. Establish Trust with ISPs

Establish Trust scrabble tiles

An excellent sender reputation is crucial for ensuring that your marketing emails reach the recipient’s inbox instead of being flagged as spam or blocked altogether. By warming up a new IP address and warming up your domain reputation, you demonstrate responsible sending practices to ISPs, which can help improve email deliverability rates over time.

No other factor can be more damaging to your placement than a low-trust relationship with the ISPs (Google, Yahoo, Microsoft, etc.).

Establishing high trust is the quickest path to sustainably improve email deliverability and is based on essentially 2 core factors:

  1. High Engagement Rates
    • What was the unique open rate vs. emails you sent
    • What was the unique click rate vs. emails that were opened
    • How many contacts replied
    • How many contacts read your email multiple times
    • How many contacts are marked as ‘important’
    • How often was your email forwarded to someone else
  2. Low Complaint Rates
    • How many people explicitly marked your message as ‘spam’
    • How many people are starting to ignore your emails (eventually, unengaged email is = unwanted email/spam to many ISPs)

Of course, there are oftentimes thousands of micro signals included in how an ISP decides to evaluate you as a sender, but if you get the 2 items above right, the rest tends to fall into place and improve email deliverability over time.

3. Gradually Increase in Email Volume

Spiral staircase or ramp for gradual domain warm up

Warming up new IP addresses and domains is an important step in establishing trust with ISPs, and monitoring sender reputation scores helps to ensure that this trust remains intact. By responding promptly to feedback loops from ISPs, you can maintain a high sender reputation score and benefit from improved email deliverability.

  • Sending Small Batches: Begin by sending only a few hundred emails daily from the new IP address/domain, targeting highly engaged subscribers who are less likely to mark messages as spam or unsubscribe.
  • Ramping Up Gradually: As your sender reputation improves, slowly increase the number of emails sent per day – ideally gradually increasing the speed at which you ramp following the Inbox Formula up until you’ve reached your daily target.
  • Maintaining Consistency: Ensure consistent volumes during this period; erratic fluctuations may raise suspicion among ISPs and negatively impact deliverability rates. Find more tips on gradually increasing email volume here.

4. Monitor Sender Reputation Scores

Monitor your email metrics and rates

These scores play a significant role in determining whether ISPs will flag an incoming message as spam or not. A good sender reputation can help ensure higher inbox placement rates for future campaigns.

A critical place to monitor for most senders is Google Postmaster Tools since 50%-80% of most email lists are made up of Gmail users or professional Google accounts at present.

Maintaining a “HIGH” domain reputation within Google Postmaster Tools is one of the leading indicators that will ultimately improve email deliverability the most among your Gmail users.

It’s worth noting though — we’ve seen customers with a medium reputation still have terrific results so long as they are diligent with your audience segmentation which we will touch on a bit later.

There are two other common tools that are very useful as a proxy to determine if there is work to be done in order to improve email deliverability.

  1. MX Toolbox: One way your sender reputation may take a hit without being wildly obvious is by getting your domain or IP on a blacklist. Not every blacklist is created equal, but if you’re looking to improve email deliverability due to a spam placement issue, it’s worthwhile to run your domain through MX Toolbox’s blacklist checker.
  2. SenderScore.org: While we’ve noticed some questionable practices to fully optimize to a “100” on SenderScore’s platform, we do know that multiple ISPs reference the sender score of your IP as one of many datapoints to evaluate the trustworthiness a sender may have, especially a new one. Particularly for non-Gmail audiences, this may be impactful and worth throwing your sending IP address into the Send Score analysis.

5. Promptly Respond to Replies

Quick reply illustration bicycles

One way to maintain a high sender score is by monitoring replies and responding promptly.

If you think about how valuable certain engagement activities are, we like to think about it like this:

The harder it is to attain a particular engagement, the more valuable it is and the better it looks in the eyes of the ISPs.

Traditionally, you can probably rank the value of engagement like this:

  1. Replies
  2. Forwards
  3. Mark as important
  4. Clicks
  5. Opens

This means that getting a reply from a subscriber is one of the most valuable things they can do and signal positive intent back to the ISPs.

But what if you get people to reply and you never reply back?

Or what if your response takes days or weeks to send off?

When you remember that a subscriber is a human, not just a data point on an excel sheet, it’s much easier to realize how unfulfilling it would be to have a slow response time from the brand or personality sending the first automated email.

Quickly replying and ideally starting a thread of multiple replies with the subscriber is like catnip to your sender reputation.

After all, when most brands are sending from a “no-reply@”, it’s a heck of a lot easier to stand out with a 10-reply thread using a real name to send from.

It will also dramatically increase the chances that your future emails are treated like human-to-human emails instead of ending up in the promo tab or worse. This makes improving email deliverability so much easier across the board.

6. Compound High Sender Reputation Scores

Stack of macarons

Maintaining high sender reputation scores is essential for improving email deliverability and achieving better results from your marketing efforts over time. Be proactive about monitoring these metrics so you can make adjustments when necessary and continue delivering valuable content directly into the inboxes of prospects and customers who actually want to hear from you.

High sender reputation will help you achieve the following:

  • Increase Email Deliverability: With a good sender reputation, you’re more likely to have your emails delivered straight into the recipient’s inbox rather than being flagged as spam, landing in the junk folder, or even the promo tab.
  • Better Open Rates: When your emails are consistently reaching recipients’ inboxes, they’re more likely to be opened and read – leading to increased open rates. This creates a virtuous cycle of reputation.
  • Fewer Spam Complaints: By ensuring that only relevant content reaches subscribers who genuinely want it, you’ll reduce the likelihood of receiving spam complaints which could negatively impact your sending reputation.

Monitoring sender reputation scores is a critical component of any successful email marketing campaign because it ensures your emails are reaching their intended audience. List segmentation based on user behavior can help further optimize the effectiveness of your campaigns by delivering personalized content tailored to each recipient’s interests and needs.

7. Segmentation Subscribers Based on Behavior

Mandarin slice segmentation

Segmenting lists based on user behavior ensures targeted content reaches relevant audiences at appropriate times, increasing overall engagement rates while reducing chances for unsubscribes or spam complaints. Properly segmenting your mailing list can lead to improved email deliverability by catering to the specific needs and preferences of each subscriber group.

List segmentation can help get:

  • Increased engagement through personalized content delivery: By analyzing user interactions with previous marketing emails, you can create tailored messages that resonate with different segments of your audience. This not only boosts open and click-through rates but also fosters a stronger connection between subscribers and your brand.
  • Reduced unsubscribe rate due to tailored messaging: When recipients receive emails that align with their interests, they are less likely to feel overwhelmed or annoyed by irrelevant information. As a result, fewer people will opt out from receiving future communications – helping maintain a healthy sender reputation and improving email deliverability in the long run.

To implement effective list segmentation strategies, consider using an advanced email marketing platform like Campaign Refinery, which offers robust tools for tracking user behavior data and automating the process of sending targeted campaigns. With these insights at hand, you’ll be better equipped to craft compelling content that keeps subscribers engaged while avoiding potential deliverability issues down the line.

List segmentation based on user behavior can help businesses increase their email engagement and reduce unsubscribe rates by tailoring messaging to the right audience. To further maximize the impact of your emails, optimizing content quality is essential for successful email marketing campaigns.

8. Optimize Content Quality

Optimize content quality

To ensure the successful delivery of emails, it is essential to prioritize content quality. ISPs often use algorithms designed specifically for detecting spam-like elements within subject lines or body text. By optimizing your content, you can avoid triggering these filters and increase the chances of your emails landing in recipients’ inboxes.

That being said, your sender reputation is even more important than content quality in order to improve email deliverability, but content still matters. A high sender reputation with mediocre or aggressive content quality may still inbox at a high rate, whereas pristine content with a low sender reputation will have a much harder time hitting the inbox.

9. Testing Subject Line Variations

Man on the moon

An effective subject line is essential for grabbing subscribers’ attention and improving open rates, which will, in turn, improve email deliverability. To find the most impactful subject lines, test different variations using A/B testing methods before sending out large-scale campaigns. This will help you identify which versions resonate best with your audience and can even inform the way you write subject lines for future emails or help guide which topics you select in the first place.

10. Optimize Body Copy

Writing a letter
  • Avoid Spam Triggers: Refrain from using excessive capitalization, exclamation marks, or words commonly associated with spam (e.g., “free,” “guarantee”). These can trigger spam filters and hurt deliverability.
  • Personalize Content: Personalizing emails by addressing recipients by their name or including other relevant information helps create a connection between sender and recipient – increasing engagement levels while reducing chances of being marked as spam.
  • Maintain Proper Formatting: Ensure that your email copy is well-formatted across various devices by utilizing responsive design techniques. This gives a consistent user experience no matter what devices your subscribers are using.

Incorporating these strategies into your email marketing efforts will not only enhance overall content quality but also contribute significantly towards helping you improve email deliverability rates.

Content Quality Optimization is an important factor to consider when attempting to improve email deliverability. By implementing authentication protocols such as SPF and DKIM, businesses can further improve email deliverability by increasing your trustworthiness as a sender by essentially signing your name to everything you do.

11. Implement Authentication Protocols

Passport authentication protocol

To improve email deliverability, it’s crucial to implement authentication protocols such as Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM). These technical measures help verify the legitimacy of incoming messages and protect sensitive information through encryption. Ensuring proper implementation can lead to better inbox placement rates.

Benefits of SPF and DKIM in Improving Email Deliverability

  • Increased trust: By authenticating your emails with SPF and DKIM, you’re signaling to ISPs that you’re a legitimate sender who is looking to build a real reputation, thus increasing their trust in your messages.
  • Better delivery rates: Emails authenticated with these protocols are less likely to be flagged as spam or rejected by ISPs, resulting in higher deliverability rates.
  • Fraud prevention: Implementing these authentication methods helps prevent phishing attacks and spoofed emails from reaching recipients’ inboxes as well as stopping others from negatively impacting your sender reputation.

Collaborating with IT Teams for Effective Implementation

In order to successfully implement SPF and DKIM protocols within your email campaigns, it’s essential to collaborate closely with your IT team or external experts. They will guide you through the process of setting up DNS records for both protocols on your domain registrar’s platform. This ensures that all outgoing emails are properly signed using the correct private keys while being verified against public keys stored within DNS records – ultimately leading towards improved email deliverability across various recipient domains.

Implementing authentication protocols is an essential step in ensuring that your emails are delivered to the right recipients and reaching their intended destinations. If you need assistance with this as a solopreneur or someone who doesn’t have an IT department within your company, Campaign Refinery is happy to assist with this step or you could hire someone on Fiverr to do it for you. Double opt-in subscription processes can further enhance email deliverability by preventing spam trap-related issues, bot signups, and more, thereby improving customer engagement.

12. Implement a Double Opt-in Process


To improve email deliverability, implementing a double opt-in subscription process is highly recommended. This method ensures that only genuinely interested subscribers join your mailing list by requiring them to confirm their subscription through a follow-up confirmation email. By doing so, you not only maintain a healthy sender reputation but also prevent potential issues related to unsolicited emails or spam traps.

Advantages of Using Double Opt-in Subscription Process

  • Better engagement: Since subscribers have actively confirmed their interest in receiving your content, they are more likely to engage with your marketing emails.
  • Fewer spam complaints: Double opt-in reduces the chances of people marking your emails as spam since they’ve explicitly agreed to receive communication from you.
  • Increase email deliverability: With fewer spam complaints and higher engagement rates throughout the rest of your sequences, ISPs will be more inclined to trust your sending reputation and ensure better inbox placement for future campaigns.

Prevention of Spam Trap-related Issues

Avoiding spam traps, which are fake email addresses used by ISPs and anti-spam organizations to identify spammers, is crucial for maintaining a good sender reputation. The double opt-in process helps protect against this issue since it requires user interaction before adding an address to the subscriber list – making it less likely that a spam trap would be included accidentally.

When incorporating these strategies into your Campaign Refinery account’s overall approach, you’re sending relevant content while ensuring proper measures are taken towards improving email deliverability.

The double opt-in subscription system is an excellent method to guarantee that your mailing list stays current and uncluttered.

It’s worth noting that in addition to a double opt-in process, it’s also important to scrub your list from all 7 types of harmful email addresses that are living on your email list right now. Only Campaign Refinery proactively removes all 7 types of these harmful subscribers from your account, but will also continually re-check your list to remove any that have turned from good to harmful over time.

By implementing graymail suppression techniques, you can further improve the deliverability of your emails.

13. Suppress Graymail

Full trash

Graymail refers to emails that recipients may have opted into but are no longer engaging with, increasing the chances of being marked as spam or ignored altogether. By analyzing contact engagement data from previous campaigns, graymail suppression tools can automatically filter out unengaged recipients – reducing overall bounce rates and increasing the likelihood of inbox placement for future sends.

  • The Role of Graymail Suppression in Improving Deliverability: Implementing graymail suppression techniques helps maintain a healthy sender reputation by minimizing complaints and unsubscribes while maximizing recipient engagement levels.
  • Importance of Sufficient Campaign Data for Accurate Analysis: Before enabling graymail suppression features within your email service provider (ESP), ensure you have sent at least a few email campaigns so that the tool has enough data to accurately identify unengaged contacts.

In addition to using automated tools provided by ESPs like Campaign Refinery, consider implementing re-engagement strategies such as sending targeted content offers or surveys designed specifically for inactive subscribers. This approach not only increases the chances of reactivating dormant contacts but also provides valuable insights into their preferences – helping further optimize future marketing efforts and ultimately improving email deliverability.

Graymail suppression is an essential technique for improving email deliverability and regularly reviewing contact lists will help to maximize open rates and click-throughs. Maintaining accurate records of contacts is critical for businesses to ensure their messaging reaches the appropriate recipients with an applicable message.

14. Create a Contact List Audit Schedule

Vacuum Cleaner vacuuming glitter off of a carpet

Maintaining an up-to-date contact list is crucial for ensuring optimal results when aiming to improve email deliverability. Regularly reviewing your lists and removing outdated addresses or unengaged contacts helps maintain high-quality recipient databases, directly impacting overall campaign performance metrics like open rates and click-throughs.

If you’re utilizing the Audience Segment feature of Campaign Refinery, this becomes easy as the segments are dynamic based on current tags and engagement, meaning your broadcast audience is always up-to-date. This, combined with our automatic list-cleaning features, means your email list is constantly de-risked and updated by default.

Impact on Open Rates and Click-Throughs by Maintaining Updated Lists

An updated list ensures that you’re sending emails to recipients who are genuinely interested in your content. This not only increases the chances of higher open rates but also improves click-through rates as engaged subscribers are more likely to interact with the content within your marketing emails.

Best Practices for Cleaning Up Contact Databases

  • Remove hard bounces: Eliminate email addresses that have resulted in permanent delivery failures due to invalid or non-existent domains.
  • Delete inactive subscribers: Identify contacts who haven’t shown signs of life (such as opening or clicking any of your emails) over a specific period (e.g., six months) and remove them from your list.
  • Avoid purchased lists: Purchased lists often contain outdated information, leading to poor deliverability rates. Focus on building an organic subscriber base through sign-up forms, gated content, and other lead-generation strategies instead.
  • Cleanse data regularly: Schedule periodic reviews of your contact database (e.g., quarterly) so you can identify potential issues early on and take corrective action promptly.

By following these best practices, you can maintain a clean and engaged contact list that contributes to better email deliverability rates for your campaigns.

FAQs in Relation to Improve Email Deliverability

Why is it important to improve email deliverability?

Email deliverability is crucial for businesses as it ensures that marketing campaigns reach the intended recipients, leading to higher engagement rates and conversions. Improved deliverability also enhances sender reputation, reduces bounce rates, and prevents emails from being marked as spam or getting blocked by ISPs.

What are some ways that a marketer can improve email deliverability?

To enhance email deliverability, marketers should warm up new IP addresses and domains, monitor sender reputation scores, segment lists based on user behavior, optimize content quality to avoid spam filters, implement authentication protocols like SPF and DKIM, use double opt-in methods for subscribers, and maintain high-quality contact lists.

How to improve domain reputation for better email deliverability?

Improving domain reputation involves sending relevant content with engaging subject lines; maintaining low complaint rates; using list segmentation strategies; implementing proper authentication protocols such as SPF, DKIM, and DMARC; regularly cleaning your contact database by removing inactive users or invalid addresses; and adhering to best practices in copywriting/formatting of emails.

What is required to maintain effective deliverability of email campaigns?

Maintaining effective email campaign delivery requires consistent monitoring of metrics like open rate (OR), click-through rate (CTR), bounce rate (BR), and complaint rate (CR); regular evaluation and optimization of campaign performance through A/B testing; keeping an updated contact list by removing unengaged subscribers and hard bounces; frequent assessment of sender/domain reputations; and following industry best practices for email marketing.

Improve Your Deliverability with Campaign Refinery

In conclusion, improving email deliverability requires a multifaceted approach that involves understanding email delivery metrics, warming up new IP addresses and domains, monitoring sender reputation scores, list segmentation based on user behavior, optimizing content quality, and avoiding spam filters, implementing email authentication protocols, and maintaining high-quality contact lists. By following the strategies and best practices outlined, your business can unlock higher revenue potential by ensuring emails reach their intended recipients.

Don’t let poor email deliverability hold back your business growth. Apply to sign up for Campaign Refinery today to get access to powerful tools that help you optimize your emails for maximum deliverability and engagement.

Happy emailing!

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