Making sure your emails actually reach your customers’ inboxes isn’t as simple as hitting send anymore.
Email deliverability is about ensuring your messages end up exactly where they need to be: in the primary inbox. Email deliverability tracks how successfully your emails make it in front of your subscribers instead of getting caught in spam filters or rejected before they even arrive.
Better email deliverability means more eyeballs on your content, more clicks on your calls-to-action, and ultimately more conversions. In this guide, we’ll break down what email deliverability actually is, the factors that influence it, and actionable ways to improve your email deliverability using current best practices for 2025.
Quick overview: email deliverability essentials
Why does email deliverability matter?
What impacts email deliverability?
How do you track your email deliverability rate?
What counts as a good email deliverability rate?
Updated email sender requirements for 2025
How to boost email deliverability
Building a deliverability-first email program
Common questions about email deliverability
Quick overview: email deliverability essentials
To keep your deliverability strong, you need to:
- Set up proper authentication by configuring Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) records, plus implementing a Domain-based Message Authentication, Reporting, and Conformance (DMARC) policy. This proves your emails are legitimate and helps them get delivered properly. Major providers like Google, Yahoo, and Microsoft now require high-volume senders to authenticate their domains and provide easy unsubscribe options, so compliance is non-negotiable for good inbox placement.
- Clean your email lists regularly to maintain strong engagement and stop wasting sends on dead or invalid email addresses.
- Stay away from spam triggers in your email content—things like deceptive subject lines, over-the-top punctuation, or cramming in too many links.
- Watch your engagement numbers including opens, click-throughs, and bounces to catch deliverability problems before they escalate.
- Target a deliverability rate of 99% or better and keep your spam complaint rate under 0.10% to maintain a good relationship with mailbox providers.
What is email deliverability?
Email deliverability is the big picture view of everything that determines whether your messages actually get through. It’s connected to how people engage with your emails and often gets confused with email delivery. Here’s the distinction:
- Email delivery means the recipient’s mailbox provider accepted your message. It confirms the email address works and the server didn’t bounce it back. However, it doesn’t tell you where that message ended up—could be the inbox, could be spam, could be somewhere else entirely.
- Email deliverability tells you whether a delivered message actually landed in a subscriber’s inbox. It’s also a critical metric for measuring how well your email marketing is performing and how engaged your audience really is.
To get a real sense of your deliverability, you need to track opens, clicks, spam complaints, bounces, and unsubscribes—and break those numbers down by mailbox provider (like Google, Yahoo/AOL, or Microsoft).
- The bottom line: When you prioritize improving your email deliverability, you increase the chances of your messages showing up right in your subscribers’ primary inbox where they belong.
Why does email deliverability matter?
Think about all the time and effort you’ve put into building a quality subscriber list and perfecting your strategy to connect with those people. If your emails never make it to their inbox, all that work goes to waste.
Low deliverability rates mean your subscribers can’t see your emails, can’t click your links, and can’t convert—which directly impacts your program’s return on investment.
What impacts email deliverability?
Getting your emails to actually land in front of people is trickier than you’d think. Email providers evaluate things like whether people are opening and clicking your messages, whether you’ve properly configured your authentication, and how consistent your sending patterns are. If you keep blasting emails to people who haven’t engaged in months, providers might decide your emails aren’t welcome and start routing them to spam.
Here’s a closer look at what really moves the needle on deliverability:
- Sender reputation: Mailbox providers judge your reputation based on signals like your IP reputation, domain history, how consistently you send, and how subscribers interact with your emails. Solid performance across opens, clicks, replies, and minimal spam complaints builds trust over time. Sudden spikes in sending volume or erratic sending schedules can raise red flags and damage your reputation. Using a consistent “From” name and recognizable domain helps build familiarity and improves your inbox placement.
- Authentication protocols: Mailbox providers depend on authentication protocols like SPF, DKIM, and DMARC to confirm that sender domains are legitimate. Without these protections—or if they’re set up wrong—your emails might get rejected outright or marked as spam.
- Email engagement metrics: When your open, click, and reply rates are weak—or your bounce and unsubscribe rates are high—your emails risk getting blocked or missing the inbox entirely. Strong engagement signals to mailbox providers that you’re a sender worth trusting.
- Spam complaints: Every time someone marks your message as spam, your deliverability takes a hit, making it harder for future emails to reach inboxes. Most experts recommend keeping spam complaints below 0.10% to avoid triggering filters or damaging your sender reputation.
- List quality: Continuing to email people who’ve checked out can drag down your engagement and hurt your sender reputation. Clean your list regularly to make sure it only contains active subscribers by purging inactive, outdated, and invalid addresses.
- Email content: What you put in your emails and how you format them plays a huge role in whether they reach the inbox or get dumped into spam. Misleading subject lines, excessive punctuation, and emails packed with links and images can all set off spam filters.
How do you track your email deliverability rate?
Unlike email delivery rate (which just shows the percentage of emails a mailbox provider accepted), email deliverability is harder to pin down because mailbox providers don’t report where accepted emails actually end up.
To understand your inbox placement, you need to look at the whole picture by analyzing multiple metrics together: bounce rates, blocks, opens, clicks, unsubscribes, and spam complaints. Monitoring these over time and comparing them across different providers can show you where your emails might be struggling. Benchmarking against industry standards also helps you figure out if changes are specific to your program or part of bigger trends affecting similar senders.
Tracking these metrics is essential, but context is everything. Some numbers might look fine at first glance but can be deceiving without the full story. For instance, low spam complaint rates might seem like a good sign, but if they’re accompanied by dropping open rates, it could mean your emails are landing in spam where subscribers never see them or can’t easily report them.
What counts as a good email deliverability rate?
Industry benchmarks suggest aiming for a deliverability rate of 99% or higher. If you’re falling below that, it usually points to problems with engagement, list hygiene, or authentication that need fixing.
Beyond deliverability rate itself, you should also keep an eye on:
- Spam complaint rate: Keep this under 0.10%. Going above this threshold can seriously damage your sender reputation and get you flagged by mailbox providers.
- Bounce rate: Aim to keep hard bounces under 2%. High bounce rates signal poor list quality and can hurt your deliverability.
- Open and click rates: While these vary by industry, consistently low engagement rates often indicate deliverability issues or content that’s not resonating with your audience.
Updated email sender requirements for 2025
Major mailbox providers have rolled out stricter requirements for bulk senders in 2025. If you’re sending to a large number of subscribers, you need to:
Authenticate your email domain using SPF, DKIM, and DMARC. This proves you’re a legitimate sender and helps protect your domain from being spoofed by bad actors.
Make unsubscribing easy by including a clear, one-click unsubscribe option in every marketing email. Subscribers should be able to opt out without jumping through hoops.
Keep spam complaints low. Google and Yahoo specifically state that senders should maintain spam complaint rates below 0.10% (and ideally under 0.03% for Gmail).
Not meeting these requirements can result in emails being blocked or sent straight to spam, so getting compliant should be a top priority.
How to boost email deliverability
Here are proven strategies to improve your email deliverability. They address common pitfalls and give you concrete steps to avoid them while boosting your inbox placement.
Segment and personalize your emails
Mailbox providers favor emails that recipients actually engage with, which means low engagement can get your messages filtered to spam.
Segmenting your list and customizing content for different subscriber groups helps keep your emails landing in the inbox. Consider creating dynamic segments based on subscriber behavior—like what they’ve browsed, what they’ve bought, and how they’ve engaged previously—plus their product or category preferences.
The more relevant your content is to the recipient, the more likely they are to click, and the better your long-term deliverability becomes. For example, a fashion retailer that sends targeted promotions based on past purchases—like showing dresses to dress buyers—will see stronger engagement and keep future emails out of spam.
Avoid common spam triggers
Spammy language and formatting can also trip spam filters. That includes things like excessive capitalization or punctuation, misleading subject lines, or packing in too many links. Even a well-intentioned subject line like “Don’t Miss Out! Your FREE Trial Is Waiting!!!” can hurt your deliverability by looking spammy.
Here’s what to keep in mind when writing your emails:
- Craft clean subject lines. Keep them short and clear, letting subscribers know what to expect so they’ll want to open. Avoid words or phrases that commonly trigger spam filters (like “free,” “act now,” “re:,” or “fwd:”).
- Keep formatting simple. Your emails should be easy to scan, with the most important info near the top. Use a good balance of images and text to communicate your message, and include a clear call to action that encourages clicks.
- Use links sparingly. Stick to two or three links maximum in your emails. Make sure all links are obviously clickable and have enough space around them for easy mobile tapping.
Test and optimize your email strategy
To make sure your emails are engaging enough to reach the primary inbox, you need to continuously test and refine them.
A/B testing different elements of your email program helps you figure out what works best for your audience (and what falls flat). Then you can use those insights to improve your approach.
- Subject line: This is the gateway to your email—the first thing subscribers see, and critical for capturing attention. Experiment with different tones, styles, and language to discover what gets your subscribers to open. For example, if you usually use straightforward subject lines, try a more playful, conversational version to see how your audience responds.
- Content: Once someone opens your email, the content is what drives conversion. This includes your copy, images, call to action, and layout. An online retailer might test whether an email featuring user-generated content performs better than one highlighting a sale. Test these elements one at a time and compare results to see what wins.
- Send time: While there are general best practices for send times, every audience is different. Test when you send campaigns to figure out which times or days of the week drive the most engagement from your subscribers.
Remember, an email with a compelling subject line and engaging content—sent at the optimal time—is more likely to get interactions, which signals to email providers that your messages are valuable and improves your deliverability.
Keep your subscriber list clean
Sometimes subscribers who were once active go quiet, and the last thing you want is to keep sending to people who aren’t opening your emails. That lack of engagement can damage your sender reputation.
Regular list maintenance is one of the most important factors for sustainable deliverability. That means removing outdated contacts and disengaged users who aren’t interacting with your messages anymore.
Set up automated workflows to identify and re-engage subscribers who haven’t opened or clicked your emails recently. You can segment these inactive contacts and run re-engagement campaigns to give them a chance to opt back in before removing them entirely.
You can even offer these unengaged subscribers the option to unsubscribe from marketing emails if they still aren’t responding after a few win-back attempts. It might feel counterintuitive, but it’s actually smart for boosting your engagement rates.
Using a double opt-in process at signup can also improve list quality and inbox placement. With double opt-in, subscribers verify their email address by clicking a link in a confirmation message after signing up. This extra step ensures your list only includes people who genuinely want your emails, reducing the risk of fake, mistyped, or spam-trap addresses getting into your database.
Building a deliverability-first email program
Watching for potential deliverability issues—like low engagement, suspicious addresses, bounces, and poor formatting—takes a lot of time and attention. Working with the right email marketing platform can help by building deliverability best practices directly into your workflow.
Look for platforms that offer:
- Built-in authentication support to make SPF, DKIM, and DMARC setup straightforward
- Automatic bounce handling that suppresses invalid addresses and prevents re-sending to known problems
- List hygiene tools that make it easy to identify and remove inactive subscribers
- Engagement tracking broken down by mailbox provider so you can spot issues early
- Expert deliverability support from teams that manage relationships with mailbox providers and stay on top of industry trends
With the right tools and processes in place, you can maintain consistently high deliverability rates and ensure your emails reach your customers’ inboxes every time.
Common questions about email deliverability
- What’s the difference between email deliverability and delivery?
Email delivery confirms your message was accepted by the recipient’s server. Email deliverability tells you whether it actually landed in the inbox or got filtered to spam.
2. What’s considered a good email deliverability rate?
A solid deliverability rate is 99% or higher. Dropping below that usually indicates issues like weak engagement, poor list hygiene, or authentication problems that need attention.
3. How can I improve my email deliverability?
Start by authenticating your domain with SPF, DKIM, and DMARC to establish trust. Focus on targeting subscribers who’ve recently engaged with your emails, since mailbox providers heavily weigh recent activity when deciding inbox placement. Maintain a clean list by removing inactive contacts, personalize your content to drive clicks, and avoid formatting or language that might trigger spam filters.
4. Why aren’t my emails getting delivered?
Emails often fail to reach inboxes due to authentication issues, outdated or invalid contacts, or high bounce and spam complaint rates. Low engagement or content that triggers filters can also prevent messages from reaching their destination.
5. What affects sender reputation?
Mailbox providers evaluate factors like your IP reputation, domain history, sending patterns, and engagement levels. High open and click rates combined with low bounce and spam complaint rates help build trust and improve deliverability.
