Do ESPs block spam traps automatically?

It's a reasonable assumption: you're paying for an ESP, it handles your sending, so surely it's watching out for spam traps on your behalf. Unfortunately, that's not quite how it works.

Spam traps are email addresses that look completely normal from the outside. They don't bounce, they don't complain, they just sit there waiting for senders who shouldn't have them to show up. That's the whole point. They're designed to be invisible to the sender, which means no ESP can reliably detect them either.

Your ESP can flag addresses with obvious formatting problems, known syntax errors, or domains that don't resolve. Some run addresses through validation services that catch a portion of risky contacts. But the traps themselves? Those pass all those checks without breaking a sweat. The only people who know a trap is a trap are the organizations that planted it.

So the real protection is upstream, not at the point of sending. A few things that actually work:

• Never buy or rent lists. Purchased lists are the fastest way to hit traps at scale.
• Use confirmed opt-in. If someone confirms their address, you know a real person is on the other end.
• Remove non-openers. Old, unengaged addresses are far more likely to have been recycled into traps over time.
• Run your list through validation before importing it. It won't catch every trap, but it removes a lot of the addresses that look suspicious.

Think of your ESP as the ship, not the coast guard. It'll carry your emails wherever you point it. Keeping the cargo clean is your job (and honestly, it's not that hard once you have a system).

If your list hasn't been cleaned in a while, or you're about to import a file from a trade show or older campaign, that's a good moment to run it through validation first. We clean lists at RME if you'd rather not do it yourself.