What is a “junk” folder vs “spam” folder?

Your subscribers don't think about folder names. But you probably do, especially when you're trying to figure out why your emails aren't landing in the inbox. Here's the short version: junk and spam are the same thing. Different name, same destination.

The folder names come down to which inbox is doing the filtering. Outlook and Microsoft 365 call it the Junk Email folder. Gmail calls it Spam. Yahoo Mail uses Spam too. Apple Mail goes with Junk. The label changes, but the job doesn't: quarantine messages the filter doesn't trust enough to block outright, but doesn't want near the inbox either.

As a sender, that distinction matters more than you might think. "Junk" at Microsoft and "Spam" at Gmail are governed by different filtering systems with different signals, different thresholds, and different ways to recover. Landing in Outlook's Junk folder often points to reputation issues tracked through Microsoft's own systems. Landing in Gmail's Spam folder can point to complaint rates, engagement patterns, or authentication gaps. Same folder concept, very different root causes.

Messages held in either folder don't sit there forever. Most providers auto-delete after 30 days. Before that, a subscriber can move your email to the inbox manually, which sends a positive signal back to the filter (essentially a vote that says "this sender is OK"). It's a small signal, but it counts.

If you're consistently landing in junk or spam at a specific provider, the folder name is the last thing to focus on. Check your sending signals first: authentication, complaint rate, engagement, and list hygiene. Those are what actually move the needle.

Not sure where your emails are landing right now? Our free blocklist checker is a decent first stop, or just reach out at our SOS hotline if things feel more urgent.