Email deliverability 101: boost your deliverability in 2026

TL;DR

• Email deliverability is the ability of your emails to land in inboxes instead of spam, driven by reputation, authentication, and engagement.
• A good email deliverability rate is typically 92–95%, with 98%+ considered excellent and anything below 85% signaling issues that can harm your email performance.
• Updated Gmail and Yahoo policies prioritize authenticated, reputable domains and penalize senders with weak compliance or high complaints.
• Improving email deliverability in 2026 requires full authentication, strong sender reputation, clean and engaged lists, proper bounce and complaint management, easy opt-outs, and well-optimized content.
• Maropost ensures a 98% deliverability rate by using adaptive sending technology, maintaining a high-trust sender environment, providing real-time deliverability analytics, and offering expert remediation support.

Statistically, nearly 50% of emails end up in spam folders. Now, imagine investing time, budget, and energy into your email campaigns – only for your emails to never reach your recipients’ inboxes. The truth is, even the best-crafted email campaigns can fail when deliverability becomes an issue. And if your messages consistently go unseen, you’re losing engagement and sales that should have been yours.

The good news is that there’s plenty you can do to ensure your emails have a better chance of reaching your subscribers. In this blog, we’ll define email deliverability, break down the key factors that impact it, and share proven strategies to help you improve deliverability in 2026.

What is email deliverability?

Email deliverability is the ability of your emails to reach your subscribers’ inboxes – not spam folders. It’s a measure of whether your email message actually lands where it’s supposed to, so your audience can see, open, and engage with it. If deliverability is strong, your emails go straight to the inbox. If it’s weak, your messages get blocked, bounced, or filtered into spam, no matter how relevant they are.

Email deliverability differs from delivery rate because an email can be marked as “delivered” yet still be sent to the spam folder, where subscribers won’t see it.

Your deliverability can be influenced by things like your sender reputation, email authentication (SPF, DKIM, DMARC), list quality, subscriber engagement levels, content quality, sending behavior, and ISP (Internet Service Provider) filtering rules.

What is a good email deliverability rate?

Although 100% is ideal but unrealistic, a good email deliverability rate typically ranges from 92% to 95%. An excellent rate often approaches 98% or above, which is common for highly engaged lists or transactional emails. If your rate falls below 85%, it signals potential issues that need your immediate attention – otherwise, the overall performance of your email marketing campaigns will suffer.

• Excellent: 98% or higher (your emails reliably reach the primary inbox)
• Good: 92–95% (you may see occasional filtering into spam or the promotions tab)
• Poor: 85%-92% (increased likelihood of spam placement or delivery blocks)

The impact of Gmail and Yahoo’s updated requirements on your email deliverability

Recent changes from Gmail (Google)

Google began rolling out stricter rules for email senders in 2024, with full enforcement in 2025. These rules mainly affect “bulk senders,” meaning anyone sending more than 5,000 emails a day to Gmail addresses. To keep their messages landing in the inbox, senders now need to:

• Prove their identity using standard email authentication tools (SPF, DKIM, and DMARC). This helps Gmail verify that the email really comes from the sender’s domain.
• Have proper DNS records for their sending IPs and use encryption (TLS) when sending messages.
• Include an easy, one-click unsubscribe link and honor opt-outs quickly.
• Keep spam complaints extremely low, ideally under 0.1% and certainly under 0.3%.

Additionally, in November 2025, Gmail ramped up its enforcement on non-compliant traffic. Messages that fail to meet the email sender requirements will experience disruptions, including temporary or even permanent rejections.

Recent changes from Yahoo Mail

In April 2025, Yahoo made a major update to how it decides which emails go to the inbox, promotions, or spam. The biggest change is that Yahoo now looks primarily at the reputation of the sender’s domain (the “From” domain), not just the sending IP address. Important changes include:

• Domain reputation is now the main factor. If the domain used in the “From” field has a poor history, messages are more likely to be filtered.
• Senders must have both SPF and DKIM set up and passing, and their “From” domain must match these authentication methods. A DMARC policy must also be published.
• Complaint rates must stay below 0.3% – based not on sent volume, but on messages that actually land in the inbox.
• Yahoo is now more strict with senders who rely heavily on promotions, affiliate content, or who send to unengaged audiences.
• Many senders have seen their open rates drop sharply (for example, 20–25% down to under 5%), not because emails weren’t delivered, but because they were redirected to folders like Promotions or Spam, or deferred as soft bounces.

How to improve email deliverability in 2026: tips and best practices

Ensure full email authentication (SPF + DKIM + DMARC)

First and foremost, make sure your sending domain is properly set up with all three protocols: SPF (which defines which servers can send mail for your domain), DKIM (which signs outgoing mail with your domain), and DMARC (which ties SPF/ DKIM alignment to the “From:” address). Without full authentication, inbox providers increasingly treat your messages as higher risk.

According to stats published by The Digital Bloom, fully authenticated domains (SPF+DKIM+DMARC) achieve 2.7x higher likelihood of inbox placement compared to unauthenticated ones:

• Full authentication: 85-95% inbox placement achievable
• Partial authentication: 55-70% typical inbox placement
• No authentication: 30-50% typical inbox placement

Keep an eye on your sender reputation

Sender reputation is a score that mailbox providers (like Gmail, Yahoo, Outlook, etc.) assign to your email-sending identity. It is calculated by using a combination of factors, including your email engagement rates, bounce rates, spam complaints, and sending volume and consistency.

Positive engagement metrics are a key factor affecting your sender reputation. What do positive interactions look like?

• Opening your emails
• Clicking your emails
• Replying to your emails
• Marking your emails as “not spam”
• Moving your emails from spam folder to the inbox
• Adding your sender domain to their address book
• Marking emails as important or starring the messages

The more of these actions your subscribers take, the better your sender reputation becomes. On the flip side, low-engagement actions like ignoring your emails, marking them as spam, or deleting them without opening can hurt your sender reputation.

Recommended reading: 11 Tips to increase your email marketing open rate in 2026

Use a double opt-in process

Using double opt-in (also known as confirmed opt-in) is one of the most effective ways to ensure better list quality. When double opt-in is enabled, here’s what happens: when people sign up for your email list, they receive an email asking them to confirm their subscription by clicking a verification link.

While that might seem tedious, it’s an excellent way to improve your list quality by filtering out bots, typos, and fake signups. Better yet, it reduces hard bounces, lowers spam complaints, and boosts your engagement metrics because confirmed subscribers are more likely to open and read your emails.

Pro tip: Use double opt-in for all high-risk list sources (like gated content, giveaways, or high-volume acquisition campaigns).

Make it easy to unsubscribe (seriously)

There was a time when businesses made it hard to unsubscribe, but today every email must include a clear opt-out link. And that’s ultimately good for your deliverability. An unengaged subscriber who ignores your messages or marks them as spam hurts your reputation far more than someone who simply unsubscribes.

But while unsubscribes are unavoidable, you can still make the most of them. Offer options like adjusting email frequency or choosing content preferences. You can also collect quick feedback on why someone is leaving.

What you should never do is hide the unsubscribe link. It increases spam complaints and violates global email and privacy laws. Once someone opts out, honor it – no “last chance” emails. If they want to return, they’ll surely find their way back.

Improve your email list hygiene

Email lists naturally decay by 20–30% each year, which means old, invalid, or low-quality addresses pile up fast and can hurt your deliverability. Here’s what you need to weed out to maintain your list hygiene:

• Duplicate addresses
• Addresses with improper structure
• Misspelled or gibberish addresses
• Addresses that may have been harvested
• Addresses with previous bounces

And while it should go without saying, buying email lists is a fast track to deliverability trouble. These lists are usually packed with spam traps, outdated addresses, and people who never showed an ounce of interest in your brand. More importantly, emailing people who never agreed (and definitely didn’t double opt-in) to hear from you isn’t just ineffective – it’s a direct hit to your sender reputation.

Handle email bounces properly

Bounces might sound a bit alarming, but at the end of the day, they simply mean your email didn’t make it to the inbox. In email marketing, bounces come in two main forms:

• Soft bounces: These occur when your message reaches the subscriber’s server but can’t be delivered due to a full inbox, temporary server issues, or a momentary block. These usually get retried automatically and might still make it through after several attempts.
• Hard bounces: These are permanent failures, typically caused by invalid or non-existent email addresses, and they won’t be retried.

Since every email service provider handles bounces a little differently, it’s worth knowing exactly how yours treats them. Effective bounce management means removing hard-bouncing addresses right away and keeping an eye on soft bounces, eventually suppressing them if they keep failing over time without any successful deliveries.

Regularly clean your list and remove disengaged contacts

Over time, once-engaged subscribers may lose interest, and inbox providers now pay close attention to how active your list really is. Instead of letting disengaged contacts sit there until they unsubscribe (or worse, mark you as spam), it’s better to take a proactive approach and just remove them.

ISPs measure spam complaints against the active portion of your list, not the total size. So, what was once a 1% complaint rate in a 10,000 person list is now a 10% complaint rate, if only 1000 addresses in that list are active.

Re-engagement campaigns can certainly revive interest, but if someone really isn’t interested in hearing from you, it’s best to just let them go. Keeping only engaged subscribers protects your deliverability and ensures your emails reach the people who genuinely want them.

Recommended reading: How REDEF achieved a 99% deliverability rate with Maropost Marketing Cloud

Watch your complaint rates

Spam complaints are never fun, but they’re not always a disaster. In fact, they can be one of the most honest forms of feedback you’ll ever receive. Sure, sometimes the issue is your send frequency, timing, targeting, or even your content. But that’s exactly why paying attention to complaints is so valuable.

While spam complaints are inevitable, what matters is identifying which emails generate the most complaints and understanding why. Those insights can help you make meaningful improvements, from fine-tuning your segments to adjusting your send times, frequency, or content. Small tweaks can often make a big difference.

Polish your email templates (every detail matters!)

Needless to say that your email content should be highly relevant to your audience. But beyond that, plenty of smaller details can also influence your deliverability. Here are some tried-and-true best practices to keep in mind when creating your email templates:

• Avoid spam-trigger words: Spam filters scan for suspicious or overly promotional language – keep your wording clean and trustworthy in both subject lines and email body.
• Check your grammar and spelling: Poor grammar hurts trust and can trigger low-quality content filters.
• Watch your tone: You may be excited about your email, but using ALL CAPS and exclamation points will set off alarms for your subscribers’ spam filters.
• Limit the number of links: Too many links can instantly trigger filters – stick to one link when possible. And no link shorteners unless you use a branded domain.
• Watch your email length: Very long or very short emails raise red flags – aim for around 500 characters for optimal deliverability.
• Use mobile-friendly templates: With 55%+ of email opens happening on mobile, responsive design is no longer optional.
• Balance text and images: Full-image emails look spammy. A ~60% text / 40% image ratio is generally considered a safe guideline.
• Keep your HTML clean: Due to spammers hiding malicious code in HTML, any messy code in your emails is seen as suspicious and will usually land your emails in the spam folder.
• Avoid large attachments: They can trigger security warnings – use a link instead.
• Structure content for easy scanning: Use short paragraphs, bullet points, headers, and clear calls-to-action.
• Test before sending: Preview emails across devices and clients to catch link issues, rendering problems, and formatting errors.

How Maropost ensures a 98% deliverability rate on your email marketing campaigns

Poor deliverability can kill even the best email campaigns before they even reach your subscribers' inboxes. That’s why you need a reliable email service provider (ESP) like Maropost. With Maropost Marketing Cloud powering your email marketing efforts, you can ensure your messages get delivered and (more importantly!) land in inboxes, not spam folders.

Here’s how we help retailers get the best delivery and deliverability rates:

• Adaptive delivery for stronger performance: Maropost’s proprietary Mail Transfer Agent (MTA) uses “Adaptive Delivery” to automatically adjust send speeds based on real-time signals from each mailbox provider. It slows delivery when providers tighten thresholds and accelerates when engagement is strong, helping maximize delivery rates.
• Stronger sender reputation through selective onboarding: Plus, we proactively protect deliverability by allowing only reputable marketers to send through our system. By keeping out spammers and senders with poor practices, we maintain a trusted sending environment that mailbox providers recognize.
• Real-time analytics and reporting: On top of that, you can generate deliverability reports that break down key metrics by ISP, helping you spot patterns in opens, bounces, and complaint rates so you can make timely, data-driven improvements to your sender reputation.
• Dedicated deliverability support and remediation: And if your sending reputation slips, our dedicated deliverability experts work with you to create a tailored remediation plan that gets you back on track. This targeted support helps restore inbox placement and has saved our clients hundreds of thousands of dollars in otherwise lost revenue.

Book a demo now to see Maropost Marketing Cloud in action and learn how it can help you run high-performing email marketing campaigns – all while ensuring a 98% deliverability rate.

Frequently asked questions

What’s the difference between email delivery and email deliverability?

Email deliverability and email delivery are often mistakenly considered the same, but they actually describe different outcomes. Email delivery confirms that a message reached the recipient’s mail server and was delivered to the mailbox, regardless of the specific folder. Email delivery measures whether the email actually reaches the inbox rather than landing in spam, promotions, or any other folder. So, an email can be delivered but still have poor deliverability if it ends up in the spam folder due to a low sender reputation.

What factors influence email deliverability?

Several key factors influence email deliverability. The most important is sender reputation, which inbox providers calculate using spam complaints, bounce rates, and how users engage with your emails. Authentication protocols like SPF, DKIM, and DMARC help verify your identity and significantly improve trust with filtering systems. Plus, your list quality, sending consistency, and highly relevant content also play an important role. Together, these signals determine whether your email reaches the inbox or the spam folder.

How can I test my email deliverability?

You can test your email deliverability by running seed tests, which send your campaigns to a network of test inboxes to see where they land – primary inbox, promotions, or spam. Pair this with inbox placement tools, blocklist checks, and DMARC/ SPF/ DKIM validation to confirm your authentication is set up correctly. Monitoring engagement signals like opens, clicks, and complaints across major ISPs also helps you quickly spot and fix issues.