Strong email campaigns don't start with great content—they start by reaching the inbox. Here's how to improve email deliverability and build a healthier email program over time.
Even the most compelling email won't drive results if subscribers never see it. Improving email deliverability isn't about chasing a single metric or finding a quick fix. It's about building trust with mailbox providers through strong authentication, relevant content, healthy subscriber engagement, and consistent sending practices.
In this guide, we'll walk through the strategies that have the biggest impact on inbox placement—from meeting today's sender requirements to optimizing your email program over time.
Before you get started
If you're new to email deliverability, start with our guide to Email Deliverability: What It Is, Why It Matters & How to Measure It. It explains how mailbox providers evaluate email programs, the metrics that matter most, and how to measure your overall sender health.
New email sender requirements for 2026
Mailbox providers continue to raise the bar for email authentication and sender quality to create safer inboxes and better experiences for recipients. While requirements evolve over time, the core expectations remain the same: authenticate your sending domain, make it easy for subscribers to unsubscribe, and send emails that people want to receive.
Google and Yahoo introduced updated sender requirements for high-volume senders in 2024, and those standards continue to shape email deliverability best practices today. If you send more than 5,000 emails per day, these requirements apply directly to your program and play an important role in maintaining strong inbox placement.
Here's what you need to know.
1. Authenticate your sending domain
Authenticating your sending domain is one of the most important steps you can take to support strong email deliverability. Mailbox providers use SPF, DKIM, and DMARC to verify that your emails are legitimate before deciding whether they belong in the inbox.
If these authentication protocols are missing or misconfigured, your emails may be filtered into spam or rejected altogether.
DMARC builds on SPF and DKIM by giving mailbox providers instructions for handling emails that fail authentication checks. It also helps protect your domain from spoofing while strengthening trust with mailbox providers.
If you haven't already implemented DMARC on your root domain, now is the time to do so.
2. Send emails from your own domain
Use your own domain in the "From" address for every marketing email. The "From" domain should also align with your SPF or DKIM records so mailbox providers can verify your identity and trust your emails.
Consistent domain alignment helps mailbox providers recognize legitimate senders and build a stronger sender reputation over time. When the "From" domain doesn't align with your authentication records, it's more difficult for mailbox providers to determine whether an email is legitimate, which can hurt inbox placement.
When you onboard your email program with Attentive, we provide the DNS records needed to authenticate emails sent through our platform using SPF and DKIM. This helps mailbox providers recognize your emails as legitimate and supports stronger inbox placement.
3. Make unsubscribing simple
Giving subscribers a simple way to opt out is part of building trust.
Google and Yahoo require high-volume senders to support one-click unsubscribe and process opt-out requests within two days. Even if these requirements don't apply to your program, making it easy for subscribers to unsubscribe is a best practice that supports a healthier email list, strengthens your sender reputation, and helps maintain strong inbox placement.
4. Send emails subscribers want to receive
Mailbox providers pay close attention to how subscribers interact with your emails. Sending messages to people who no longer engage can increase spam complaints, weaken engagement signals, and make future inbox placement more difficult.
Google and Yahoo recommend keeping spam complaint rates below 0.10%. The best way to stay below that threshold is to send relevant, timely emails to subscribers who want to receive them. That means regularly cleaning your email list, honoring unsubscribe requests promptly, and sending content that's aligned with subscribers' interests and expectations.
If you're an Attentive Email customer, our Email Deliverability team proactively monitors your email program to help you maintain strong sender health, identify potential issues early, and optimize inbox placement over time.
How to improve email deliverability
Strong email deliverability isn't the result of a single change—it's the outcome of consistently earning trust with subscribers and mailbox providers. These best practices can help you strengthen sender reputation, improve inbox placement, and create better experiences for your audience.
Segment your audience and personalize every message
Mailbox providers use recipient engagement as an important signal when determining inbox placement. The more relevant your emails are, the more likely subscribers are to open, click, and engage with them over time.
One of the simplest ways to improve performance is to segment subscribers based on previous engagement and purchase behavior. Compare how campaigns perform for subscribers who have previously opened or purchased with those who haven't. These audiences often behave very differently, and understanding those patterns can help you tailor your messaging, improve engagement, and support stronger inbox placement.
From there, build dynamic audience segments using signals like browsing behavior, purchase history, product preferences, and previous engagement. The more relevant your messages are to each subscriber, the more opportunities you create for meaningful engagement—and the stronger your inbox placement can become over time.
Monitor your deliverability performance
Improving deliverability starts with understanding how your email program is performing. Rather than focusing on a single metric, monitor a combination of delivery, engagement, and sender health metrics over time to identify trends before they affect inbox placement.
If you're an Attentive Email customer, the Deliverability Dashboard brings these metrics together in one place, making it easier to monitor delivery rates, engagement, spam complaints, and bounce rates so you can quickly identify opportunities to strengthen sender health and improve inbox placement. Learn more in our Deliverability Dashboard documentation.
Build emails subscribers trust
Your email content influences more than opens—it shapes how subscribers perceive your brand. Clear, relevant emails encourage engagement, while misleading subject lines or cluttered formatting can erode trust and increase the likelihood of spam complaints.
Here are a few best practices to keep in mind:
- Write clear, relevant subject lines. Set accurate expectations and avoid misleading language designed only to drive opens.
- Keep your formatting simple. Make emails easy to scan by leading with the most important information, balancing text with images, and including a clear call to action.
- Use links intentionally. Include only the links subscribers need to take the next step, and make sure they're easy to identify and tap on mobile devices.
Every subscriber interaction sends a signal to mailbox providers. Building emails subscribers trust helps strengthen engagement over time, supporting better inbox placement.
Test, measure, and refine your strategy
Deliverability isn't static. Subscriber preferences change over time, so regularly testing your email program helps you understand what resonates with your audience and where you can improve.
A/B testing subject lines, content, calls to action, and send times can uncover valuable insights—but reliable results depend on testing comparable audiences. For example, if one subject line is sent to a larger share of subscribers who have previously opened or purchased, it's likely to outperform the other regardless of the subject line itself. Keeping audience segments balanced helps ensure you're measuring the impact of your test—not differences in your audience.
Here are a few areas worth testing:
- Subject lines: Experiment with different messaging styles, lengths, and tones to learn what encourages subscribers to open your emails.
- Email content: Test different copy, imagery, layouts, and calls to action one variable at a time so you can clearly understand what influences engagement.
- Send time: Test different days and times to determine when your audience is most likely to engage.
Over time, these insights can help you deliver more relevant experiences that strengthen subscriber engagement and support better inbox placement.
Maintain a healthy subscriber list
Subscriber engagement naturally changes over time. Some subscribers become less active, while others may no longer want to hear from your brand. Regular list maintenance helps you focus on the people who are most likely to engage while protecting your sender reputation.
Remove invalid email addresses, suppress hard bounces, and regularly review inactive subscribers. If you're migrating to a new email platform, be sure to carry over your suppression list so you don't accidentally resume sending to addresses that previously bounced.
Attentive's sunset segments and journeys make it easier to identify subscribers who haven't opened or clicked your emails recently. Before removing them entirely, consider running a targeted re-engagement campaign to give them the opportunity to opt back in.
Using a double opt-in process can also improve list quality from the start. Asking subscribers to confirm their email address helps reduce invalid signups and ensures your list is made up of people who genuinely want to hear from your brand.
While it may seem counterintuitive, giving unengaged subscribers an easy way to unsubscribe is often healthier than continuing to send emails they no longer want. Over time, a smaller, more engaged subscriber list leads to stronger engagement signals and better inbox placement.
How Attentive helps improve email deliverability
Maintaining strong email deliverability takes ongoing attention. As mailbox provider expectations evolve, monitoring engagement trends and protecting your sender reputation become even more important.
Attentive builds deliverability best practices directly into the platform so you can spend less time troubleshooting and more time creating campaigns your subscribers want to receive. Our Email Deliverability team works closely with mailbox providers, monitors industry trends, and proactively helps customers identify and address potential issues before they impact inbox placement.
The Deliverability Dashboard gives you a centralized view of the metrics that matter most, including delivery rates, engagement, spam complaints, and bounce rates. By monitoring these signals in one place, you can better understand your email program's health and identify opportunities to strengthen sender reputation over time. Learn more about the Deliverability Dashboard in our Help Center.
Combined with a 99%+ delivery rate and expert deliverability guidance, Attentive gives you the tools and support to build a healthier email program and consistently reach your subscribers' inboxes.
Ready to strengthen your email program? Explore Attentive Email to learn how we help brands improve inbox placement, protect sender reputation, and create more personalized customer experiences.
Deliverability is an ongoing process
Improving email deliverability isn't something you check off once and forget. Mailbox providers continuously evaluate authentication, engagement, sender reputation, and sending practices, which means maintaining strong inbox placement requires ongoing attention.
By monitoring the right metrics, testing your email program, and creating experiences subscribers genuinely want to engage with, you can build stronger sender reputation and support long-term email performance.
Ready to strengthen your email program?
Attentive helps brands improve inbox placement with built-in deliverability best practices, proactive monitoring, and expert guidance from our Email Deliverability team.
Learn more about Attentive Email and discover how we help marketers create more personalized customer experiences that reach more inboxes.
Frequently asked questions about improving email deliverability
1. How long does it take to improve email deliverability?
Improving email deliverability takes time because mailbox providers evaluate sending behavior and subscriber engagement over time. While technical updates like authentication can have an immediate impact, building sender reputation is an ongoing process.
2. What's the fastest way to improve inbox placement?
Start by authenticating your sending domain, cleaning your subscriber list, and focusing on subscribers who actively engage with your emails. These changes help strengthen sender reputation and improve inbox placement over time.
3. Does landing in the promotions tab mean my email has poor deliverability?
No. For many marketing emails, landing in the Promotions tab is expected and still counts as successful inbox placement. The goal is to consistently reach the inbox—not necessarily the Primary tab.
4. How often should I monitor deliverability?
Review key metrics like delivery, engagement, spam complaints, and bounce rates regularly to identify trends before they become larger issues. Monitoring performance over time is more valuable than reacting to a single campaign.
