What’s Gmail’s approach to “domain reputation vs IP reputation”?

If you've ever switched ESPs hoping to leave a bad reputation behind, here's the thing: Gmail already saw that coming. Gmail weights domain reputation significantly more than IP reputation, and that domain reputation travels with you everywhere you send from.

The reason makes sense when you think about how modern sending works. Most senders today use shared IP pools through their ESP, which means dozens or hundreds of brands are sending from the same IP addresses. Filtering purely on IP would produce too many false positives, so Gmail shifted its focus to the domain, which is something only you control.

What feeds domain reputation? Engagement signals matter a lot: how often your emails get opened, whether recipients report them as spam, how many bounce, and whether your authentication (SPF, DKIM, DMARC) is clean and consistent. If your engagement signals are strong, your domain reputation tends to hold up even if the shared IP you're on has a rough patch.

The flip side is equally real. You can't outrun a damaged domain by migrating to a new ESP or a different IP range. If your domain carries the damage, it follows you over. This is why inbox placement on Gmail responds much faster to fixing your sending practices than to any infrastructure change.

IP reputation still counts, especially for high-volume senders on dedicated IPs, but for most marketers on shared infrastructure it's the secondary signal. Gmail Postmaster Tools reports both separately, so you can actually see which one needs attention for your specific domain. If you haven't set that up yet, it's free and genuinely useful.

The practical takeaway: treat your domain like the asset it is. Consistent authentication, clean lists, and engaged subscribers protect it better than any IP switch ever could.