If your emails keep landing in spam, you don’t have a copywriting problem. You have a deliverability problem.
Email deliverability is the single biggest factor that decides whether your outreach drives revenue or disappears into the void. And yet, most marketers and sales teams only pay attention to it after they see open rates tank.
This guide covers everything you need to know about email deliverability in 2025: what it is, why it matters, what hurts it, and most importantly, how to fix it so your emails actually land in the inbox.
Email deliverability is the ability of your emails to land in the inbox, not just “get sent” or “avoid bouncing.”
Think of it this way:
If you’re sending cold emails, newsletters, or transactional updates, deliverability is the invisible gatekeeper. Ignore it, and even the best-crafted campaign will never be seen.
Inbox providers like Gmail, Outlook, and Yahoo use hundreds of signals to decide where your emails go. Here are the biggest culprits when your emails end up in spam:
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👉 Related reading: Why Are My Emails Going to Spam?
Mailbox providers track how your domain behaves over time. If your emails consistently get ignored, marked as spam, or bounced, your domain reputation tanks.
If you’re using a dedicated SMTP or IP, its reputation matters too. Shared IPs can hurt if someone else on the same pool is spamming.
These DNS records tell inboxes, “Yes, this sender is legit.” Without them, your emails look suspicious.
Spam filters scan your subject lines, body text, and links. Overuse of trigger words, too many images, or sketchy links can get you flagged.
Providers weigh how recipients interact. If your emails are opened, clicked, and replied to, that’s a positive signal. If they’re ignored or marked as spam, your reputation suffers.
Here’s the playbook we recommend to anyone struggling with inboxing:
👉 Here's a full setup guide for SPF/DKIM/DMARC you can follow.
Sending volume out of nowhere = instant red flag. A proper warm-up process slowly builds trust with providers.
Mailivery automates this by running human-like conversations between your inbox and a network of real, trusted mailboxes. That activity signals to Gmail, Outlook, and others that your domain is safe.
👉 Learn why warm-up is important in our post Email Warm-Up Explained: The Missing Step in Your Deliverability Strategy
Never buy lists from unknown sources and always re-verify your purchased lists. Even verified purchased data has spam traps and dead addresses. Use list-cleaning before sending and consider double opt-in if you’re running marketing campaigns.
👉 See Mailivery’s advice on email list verification
Skip the caps-lock shouting, “FREE trial” promises, and shady links. Keep subject lines natural and body text conversational.
👉Use this free spam words checker to audit your content.
Ramp slowly. A fresh domain shouldn’t send 1,000 cold emails in week one. Start small, scale gradually, and rotate inboxes if you’re running larger campaigns.
Track inbox placement rates, spam folder percentages, and reputation signals. Don’t fly blind. Tools like Mailivery give you real-time deliverability metrics.
The key is combining monitoring with proactive fixes. That’s why most teams use a warm-up + testing solution.
What is a good deliverability rate?
Generally, 95%+inbox placement is considered strong. Anything below 85% needs fixing.
How do I know if my emails are going to spam?
Run an inbox placement test. Mailivery’s test checks across Gmail, Outlook, Yahoo, and more.
Does email warm-up really work?
Yes, when it’s done with real, trusted mailboxes that mimic natural behavior. Mailivery’s warm-up improves reputation by showing consistent engagement.
How long does it take to fix deliverability issues?
Depends on severity. A domain with mild issues may recover in 1–2 weeks. A heavily burned domain could take months.
Marketers obsess over subject lines, SDRs worry about personalization, but none of that matters if you’re not inboxing.
Deliverability is about building trust. Trust with Gmail, Outlook, and every provider your prospects use.
At Mailivery, we help you build that trust automatically. Our warm-up network, deliverability checks, and inbox placement tests give you the foundation you need, so every email has a fighting chance.
👉 Try Mailivery today and start landing in the inbox where your emails belong.
The easiest way to get responses to your cold emails.
