Clients ask for a dedicated IP assuming it's a strict upgrade. It isn't. Below a certain volume, it's a downgrade that looks like an upgrade.
A shared IP pools reputation across every sender your ESP places on that address. Your sends build the reputation, but so do every other tenant's sends, good and bad. Most ESPs manage this pool actively, removing abusive senders to protect it, which is why a well-run shared IP from a major provider often has a stronger, more established reputation than a brand-new dedicated IP would on day one.
Low or inconsistent volume is the clearest case. A dedicated IP needs regular sending to stay warm, and if your volume varies week to week or sits below real scale, you're better off on a shared IP that's already warmed by aggregate volume from everyone on it. New senders also benefit from starting shared, since it skips the warming period a dedicated IP requires before earning trust.
High, consistent volume, most ESPs and specialists put the threshold around 100,000 sends a month, is where a dedicated IP starts paying off. At that volume, you generate enough regular traffic to build and maintain your own reputation, and you're no longer exposed to another tenant's bad behavior tanking your inbox placement. You also get direct visibility into your own reputation data without another sender's noise mixed in.
A dedicated IP without consistent volume to support it decays between sends, since mailbox providers need regular, predictable traffic to maintain trust in an address. A company that moves to a dedicated IP too early, then sends in sporadic bursts, ends up with worse deliverability than they had on a shared IP, because a cold, erratic dedicated IP reads as more suspicious than steady volume on a shared one ever did.
Already on a dedicated IP and seeing problems? Check your reputation directly in Microsoft SNDS and Google Postmaster Tools before assuming the IP itself is the problem. Inconsistent volume on a technically fine IP produces the same symptoms as a bad one.
Most ESPs and deliverability specialists put the threshold around 100,000 consistent monthly sends. Below that, a dedicated IP struggles to generate enough volume to maintain its own warm reputation, and a cold, inconsistent dedicated IP delivers worse than a shared one.
Yes. IP reputation reflects everyone sending from that address, so a spammy sender sharing your IP can drag down inbox placement for every other tenant on it, regardless of their own sending practices. This is the core argument for a dedicated IP once volume supports one.
The IP's reputation decays between sends, since mailbox providers need regular, predictable volume to maintain trust. Sporadic bursts on a cold, decayed IP look more suspicious to filters than steady volume on a shared IP ever did, which is the dedicated IP trap.
Send us your actual monthly volume and send pattern. We'll tell you whether it's the right move yet.
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