What is the role of sender reputation in placement?

Think of sender reputation as your running scorecard with mailbox providers. Every email you send either adds points or takes them away. And that score follows you directly into the inbox vs spam decision.

Reputation lives at two levels, and both matter. IP reputation tracks the history of the specific server address your emails come from. Domain reputation tracks your sending domain's long-term behavior. Gmail leans heavily on domain reputation these days, which means switching to a fresh IP won't wipe the slate clean if your domain has a troubled history.

What actually shapes your reputation? The big factors are:

• Spam complaint rate. If too many recipients hit "Report spam," your reputation takes a hit fast. Gmail flags anything above 0.10% as a warning sign. Above 0.30% and you're in serious trouble.
• Bounce rate. High hard bounce rates signal that you're sending to addresses that don't exist, which looks like purchased or neglected lists.
• Engagement. Opens, clicks, replies, and moves to inbox all tell mailbox providers your emails are wanted. Low engagement over time quietly drags your score down.
• Authentication. Properly set up SPF, DKIM, and DMARC don't boost your reputation on their own, but missing them makes every other signal harder to trust.
• Sending consistency. Erratic volume spikes, sending 500 emails one week and 50,000 the next, looks suspicious and can trigger throttling.

Good reputation earns a kind of quiet benefit of the doubt. Your emails skip the heavy scrutiny and land in the inbox even if a subject line or link looks slightly unusual. Poor reputation means the opposite. Clean, well-written emails can still land in spam when the sender behind them has a damaged score. Content alone can't save you if the reputation isn't there.

It's also worth knowing that reputation decays in both directions. You can rebuild a damaged reputation by cleaning your list, reducing sending frequency, and improving engagement. But you can also slowly damage a healthy reputation by sending to disengaged subscribers for too long without a sunset policy. (Of course, that's the part most senders find out only after the damage is done.)

If you're not sure where your reputation stands right now, our free Blocklist Checker is a quick starting point. Or if things are already going sideways, our SOS hotline is free and we actually pick up.