What is Email Deliverability?
Email deliverability is the ability to land in the inbox of our subscribers and prospects. Imagine spending thousands crafting beautiful emails—only for them to land in the spam folder, never to be seen. Or the promotions tab, where they’re buried under endless discounts from competitors.
Furthermore, in June 2025 Google rolled out the Manage Subscriptions feature in Gmail, which allows users to unsubscribe from email lists with a single click, a move designed to declutter inboxes and give users more control over their digital communication.
This is the harsh reality many brands face with email deliverability. The good news? You can fix it.
Let’s break down exactly how inbox providers decide where to place your emails, why you might be landing in spam, and give you a step-by-step roadmap to achieve perfect deliverability in just six weeks.
Note: You can use Glock Apps or Google Postmaster Tools to test your email deliverability and see where your emails are being delivered at Gmail, Outlook and all major ISPs.
Why Inbox Placement Matters So Much
Gmail, Outlook, Apple Mail, and other inbox providers all have one mission:
✅ To give their customers (your subscribers) the best experience possible.
That means showing them emails they:
- Actually want to read
- Consistently open
- Frequently click
- Never mark as spam
If your emails check these boxes, they’ll land in the Primary tab.
If they somewhat check these boxes (like typical marketing emails), you’ll end up in Promotions.
If you fail to check these boxes, you’re off to the Spam folder.
The Harsh Truth: Your Open Rate Tells All
In the eyes of inbox providers like Google, your open rate is your credit score.
- If only 2 out of 10 people open and engage with your emails (20%), it sends a signal to Google that people don’t care about your content.
🔥 Result: Spam or the promotions folder. - Ideally, you want to be at 45%+ open rates with click rates over 1%, bounce rate less than 1%, spam complaint rate less than 0.01% and unsubscribe rate less than 0.5%.
🔥 Result: Primary inbox placement, higher clicks, more sales.
What Impacts Email Deliverability?
The following key factors determine email deliverability:
Sender Reputation – Your sending history matters. Internet service providers (ISPs) track how recipients interact with your emails. High engagement (opens, clicks, replies) boosts your reputation, while ignores, spam complaints, high bounce rates, and mass sending from a new domain can quickly damage it — even getting you blacklisted. Regular list hygeine and engagement metrics like click rates are key for maintaining a positive sender reputation. Google recommends keeping your spam rate below 0.1% for best deliverability. Rates above 0.3% in Gmail can harm your sender reputation, trigger sending limits, reduce inbox placement, and even risk blacklisting.
Email Authentication – Protocols like SPF, DKIM, and DMARC verify that your emails are genuinely from your domain. Without them, your messages are more likely to be flagged as spam or blocked altogether. When SPF, DKIM, and DMARC are all correctly set up, your emails are more trusted by ISPs, improving deliverability and reducing the risk of your messages being marked as spam.
List Quality & Engagement – Clean, targeted lists perform better. Sending to unengaged or purchased lists increases bounce rates and spam complaints, signaling to ISPs that your emails are unwanted.
Content & Frequency – Poorly designed emails, spammy subject lines, or excessive sending can harm deliverability. Consistent, valuable content at a reasonable frequency keeps engagement high and your sender reputation healthy. Before sending, you can use a spam checker tool to check if any words you have used in your plain text email could trigger spam filters.
Email Warm-up – When you start sending from a new domain, mailbox providers don’t know whether you’re a legitimate sender or a spammer. The warm-up process involves gradually increasing the sending volume of your emails over time in order to build or recover strong sender reputation. For example, if you are a relatively new domain and you immediately blast out one thousand emails to cold contacts in a single day, it will raise instant red flags with mailbox providers.
If recipients ignore the emails, delete them, or mark them as spam, this signals to ISPs that the sender is unwanted, increasing the likelihood of throttling, blocking, or outright blacklisting. Once blacklisted, even legitimate future campaigns from that domain will struggle to reach inboxes, forcing the brand to rebuild trust — a slow and costly process.
IP reputation This is essentially the “trust score” that mailbox providers (like Gmail, Outlook, and Yahoo) assign to the IP address you use to send emails. Many ESPs such as MailChimp use shared IP addresses for sending emails,meaning many users share the same IP address. This means the reputation of that IP is shared among all users on it. If one user sends spam, it can negatively affect the deliverability of emails for all other users on the same IP. However, most ESPs also offer the option to use a dedicated IP address for an additional fee.
How to Build Up Your Sender Reputation (and Escape the Spam Folder)
You’re going to train inbox providers to see your emails as high-value, highly engaging content that people WANT.
The core strategy?
✅ Only send emails to people who are already engaging.
✅ Stop sending to people who ignore you.
✅ Slowly expand as your reputation improves.
The 6-Week Deliverability Bootcamp
Here’s your exact roadmap to get out of spam and into the primary inbox:
🔥 Week 1-3: Build Engagement With Your Most Active Subscribers
- Create hyper-engaged segments:
- 14-day engaged list (people who opened in last 14 days)
- 30-day engaged list
- 60-day engaged list
- 90-day engaged list
- Remove anyone with hard bounces, unsubscribes, or spam complaints.
- Turn off all automated flows except:
✅ Welcome
✅ Browse abandonment
✅ Cart/checkout abandonment
✅ Post-purchase
(These have the highest engagement and help rebuild trust.) - Run highly engaging campaigns 2x per week to only your 14-day engaged list.
- Use fun quizzes, shocking stats, exclusive offers—anything that gets opens and clicks.
🚀 Week 3-4: Expand as Your Open Rates Climb
- Once your 14-day engaged list hits 50%+ open rates, start emailing your 30-day engaged list 2x per week.
- Keep campaigns fresh and dopamine-inducing.
(Think: memes, short stories, polls, juicy deals.)
⚡ Weeks 5-6: Solidify Your Reputation
- Monitor your open rates—don’t let them drop below 45-50%.
- Once your 60-day engaged list consistently gets 50%+ opens, expand further.
🏆 Week 6+: Maintain and Scale
- Now you can email your 90-day engaged list, sending 2 campaigns per week.
- To reach beyond, send 1 broad campaign per month to a slightly expanded list.
Never blast your entire email database.
- Many old emails are inactive, fake, or might have flagged your domain.
- Keep pruning dead weight to protect your sender reputation.
Bonus Tips to Supercharge Your Deliverability
✅ Warm up new sender domains properly.
Send small, engaged campaigns at first. Gradually ramp up.
✅ Avoid spammy words in your email.
Using words and phrases considered as spammy in an email — such as “lowest prices ever”, “100% free,” “urgent,” or “guaranteed” — can trigger spam filters and reduce deliverability, as ISPs often flag these terms as indicators of unsolicited or deceptive messages. Beyond wording, poor formatting, excessive punctuation, or overuse of capital letters can also raise red flags. Tools like Mail Tester, SpamAssassin, and Folderly help identify these risks by scanning your email content for known spam trigger words, formatting issues, and suspicious patterns. Once issues are flagged, A/B testing allows you to compare different subject lines, body text, and calls-to-action to find phrasing that engages recipients without tripping spam filters, ultimately improving inbox placement.
✅ Authenticate your emails.
Ensure SPF, DKIM, and DMARC are properly set up. (Your ESP or developer can help.)
✅ Make it easy to unsubscribe.
This might be counterintuitive, but it lowers spam complaints—which helps deliverability. People unsubscribe for dozens of reasons that have nothing to do with the quality of your emails:
- They’re overwhelmed and cutting back.
- They no longer need the products or services you provide.
- They signed up just for your freebie.
- Their inbox is too full.
✅ Get a dedicated IP.
A dedicated IP is often better than a shared IP for email deliverability because you have full control over its reputation. With a shared IP, your deliverability depends on the sending behavior of all other senders using that IP — if one sender spams or violates best practices, the entire IP’s reputation suffers, potentially causing your emails to land in spam. A dedicated IP eliminates this risk by isolating your sending activity, allowing you to build and maintain a strong reputation with Internet Service Providers (ISPs) based solely on your own email practices. This means you can implement consistent sending patterns, maintain low spam complaint rates, and gradually warm up your IP to maximize inbox placement over time.
✅ Encourage replies.
One simple way to boost engagement with your emails is by asking subscribers to reply with a single word—like “yes.” This low-friction request removes barriers to interaction and makes it effortless for people to engage. The act of replying signals to inbox providers that your messages are valuable, which can improve deliverability. It also opens a direct conversation with your audience, helping you build stronger relationships while keeping your list active and engaged.
The Bottom Line
Inbox providers are obsessed with user experience.
If your emails look loved—opened, clicked, replied to—you’ll be rewarded with prime inbox real estate.
If they’re ignored or annoy people, they’ll be banished to spam.
By following this 6-week deliverability rehab plan, you’ll prove to inbox providers that your emails belong in the primary tab—where they’ll actually be seen, opened, and drive sales.
