How to test for “silent junking”?

Your open rates just fell off a cliff at one provider, but there are no bounces. No errors. No complaints. The emails are being accepted and then... silence. That's silent junking. Your messages are landing in spam (or being filtered out entirely) without any notification coming back to you.

Here's how to actually test for it.

Set up seed accounts at the major providers

Create personal test accounts at Gmail, Outlook, Yahoo Mail, and any other provider your audience uses heavily. Send your next campaign to those addresses and check both the inbox and the spam folder. Write down where each one landed. Do this for a few sends in a row, not just one. A single test can be misleading if you hit a timing fluke.

Ask real humans to check

Seed accounts are useful, but they're clean, unengaged inboxes with no history. Real recipients get treated differently. Ask a few colleagues or trusted contacts at different email providers to look in their spam folders after your next send. This sounds low-tech, but it catches things your seeds won't. An inbox that's been ignoring your emails for two months looks very different to a spam filter than a fresh test account does.

Dig into your open rates by provider

Most ESPs let you segment open rate data by recipient domain. Pull it. If your Gmail open rate is running at 35% and your Outlook open rate is 4%, that's not a content problem. That's a placement problem at Outlook. A dramatic gap between providers is one of the clearest signals that silent junking is happening somewhere specific (and it makes your next troubleshooting step obvious).

Zero engagement from a whole domain is even more telling. If you have 500 Outlook addresses on your list and not a single open in six weeks, something is filtering your mail before it ever hits the inbox.

Use an inbox placement tool

Third-party inbox placement services like Mailtrap run a broader panel of real inboxes across providers, regions, and client types. They show you where your mail actually lands, inbox vs. spam vs. missing entirely, across a much wider sample than a handful of seed accounts can provide. This gives you the most complete picture, especially if you're sending across multiple countries or industries with different filtering setups.

You can also run your email source through our free Email Header Analyzer to check whether your authentication signals are passing cleanly. Failing SPF, DKIM, or DMARC doesn't always cause a hard rejection. Sometimes it just quietly tips a filter toward spam.

What to do once you've confirmed it

So if your seeds and open rate data both point to a specific provider silently filtering your mail, that's your next investigation. Check whether you're on any blocklists, look at your authentication results at that provider, and review whether your sending behavior recently changed in a way that might have triggered a reputation drop. The silence has a cause. You just have to go find it.

If you're stuck or things are actively broken, our SOS hotline is free. No pitch, just help.