What’s the difference between “delivered” and “accepted”?

Your ESP says 9,800 emails were "delivered." Does that mean 9,800 people can read them in their inbox right now? Not necessarily. And that gap matters.

"Accepted" is the precise technical term for what happens when the receiving mail transfer agent (MTA) confirms it received your message with a 250 OK response. That's the moment the SMTP handshake completes and responsibility shifts from your sending server to theirs. Most ESPs call this "delivered" in their reporting dashboards, even though "accepted" is more technically accurate.

Here's the thing: neither term tells you anything about where the message ended up inside the mailbox. An accepted message might sit in the inbox, spam folder, promotions tab, or anywhere else the mailbox provider decides. Delivery and inbox placement are completely separate events. Your ESP has no visibility into what happens after the 250 OK response.

This is why a campaign can show 98% "delivered" in your ESP report while half of those emails are sitting in spam folders. The ESP tracked acceptance, not placement. To actually see where your emails land, you need inbox placement testing. And if you want to understand what's driving placement decisions, your bounce rate and sender reputation are usually the places to start.