How to confirm you’re hitting the spam folder (not blocked)?

Your open rates have quietly dipped, but your delivery rate still looks fine. No bounces, no hard errors. So what's actually going on? There's a real difference between your email being blocked (turned away entirely) and being spam-foldered (delivered but hidden). Confirming which one you're dealing with changes everything about how you respond.

Here are four ways to figure out which one you're up against.

1. Send to your own inboxes first

This sounds obvious, but it's the fastest sanity check. Send a test to your own accounts at Gmail, Outlook, and Yahoo Mail. Don't just watch for delivery. Open the spam folder and check. If the email shows up there, you're being spam-foldered, not blocked. Blocked emails never arrive at all.

2. Check Gmail Postmaster Tools

Gmail Postmaster Tools shows you delivery errors that indicate actual blocking. If your domain or IP is being rejected, you'll see error spikes there. If there are no delivery errors but your reputation score is low (shown in the Domain Reputation dashboard), that's a strong signal that Gmail is accepting your mail and quietly routing it to spam. No errors plus low reputation usually equals spam foldering.

3. Compare delivery rate to open rate

And this is the logic worth understanding. A blocked email never delivers. So if your delivery rate is high (say, 98%) but your open rate has fallen off a cliff, that gap is telling you something. The messages are arriving somewhere, just not the inbox. High delivery plus low engagement is the classic fingerprint of spam folder placement.

4. Run a seed test

Seed testing means sending your campaign to a set of test accounts spread across different mailbox providers and inbox types, then checking where each one lands. Tools like Mailtrap let you do this in a controlled environment. You can also build a small manual seed list yourself using free accounts across Gmail, Outlook, Yahoo, and any other providers your real audience uses. Check the inbox and the spam folder at each one after sending. If messages consistently land in spam across multiple providers, that confirms placement is the issue, not just a one-provider quirk.

Still once you've confirmed spam foldering (and ruled out a full block), the next question is whether the cause is your content, your sender reputation, or your authentication setup. That's where the real diagnosis begins.

Not sure where to start? Check your blocklist status first with our free tool, then go from there.