Shared IPs are hurting your deliverabilityYour inbox rate is coupled to senders you have never met.

A shared IP is one address handling mail from many different sending accounts at once, which is how most ESPs keep costs down for smaller senders: nobody pays for exclusive use of an IP address they are not sending enough volume to justify on their own. The tradeoff is that mailbox providers do not evaluate each tenant on that IP individually in real time. They watch the IP's overall pattern: aggregate complaint rate, aggregate bounce rate, spam-trap hits across everyone using it, and score accordingly.

That scoring is why a well-run pool can work fine for years and then have one bad week that is not yours. Your content, your list hygiene, and your send cadence can all be spotless, and your inbox placement still dips because a different sender on the same IP had a bad list import or a compromised account that started blasting.

The coupling runs in one direction that matters most: reputation can drop faster than it recovers. A pool operator can suspend the offending sender within hours of noticing a spike, but the IP's reputation with Gmail, Outlook or Yahoo does not reset the moment the bad sender is gone. Mailbox providers weight recent history heavily, so the pool carries the mark for a period afterward, and every other tenant on it, including you, inherits that period.

You also cannot see it coming. There is no dashboard that shows you who else is on your specific IP or what their sending pattern looks like this week, which means a shared-pool sender is, structurally, taking on risk it has no visibility into and no ability to manage directly.

Domain reputation, authentication and engagement stay yours regardless of the IP arrangement. IP reputation is the odd one out on a shared pool: it is the single signal in that list that belongs to a group of senders rather than to you specifically, which is exactly why it is the signal worth understanding before you assume a deliverability dip is something you did.

It removes the neighbors, and it introduces a different problem: a fresh dedicated IP has no sending history at all, so mailbox providers treat it as unknown rather than as trusted. It has to be warmed, meaning volume ramped gradually over weeks while complaint and bounce rates are watched closely, before it earns the kind of trust a mature shared pool already has. On Amazon SES, a standard dedicated IP runs $24.95 a month; a managed one, where AWS handles the warm-up schedule, is $15 a month plus a per-email fee, current as of the 1 September 2026 pricing check.

The honest comparison is not shared-bad, dedicated-good. It is shared-uncontrolled-risk versus dedicated-controlled-effort. A dedicated IP only pays off once your volume is steady enough to keep it consistently warm; an IP that goes quiet for weeks between sends can lose the trust it built, which puts a low-volume sender back closer to square one anyway.

• Your volume is low and inconsistent, so a dedicated IP would spend more time cold than warm, and a mature shared pool's existing reputation serves you better than an IP you cannot keep active.
• You are on a reputable ESP that actively monitors and removes bad actors from its pools quickly, which shortens how long any dip actually lasts.
• You are early enough in sending that the operational cost of monitoring and warming a dedicated IP is not worth taking on yet, and the occasional shared-pool dip is a manageable cost of doing business at this stage.

SendBunny installs into your own AWS account and sends through your own Amazon SES identity rather than a shared marketing-platform pool. Reputation still follows the account, and Amazon SES's own reputation dashboard shows your bounce and complaint rates directly, so you are watching your own numbers rather than an aggregate you cannot see into. It does not fix a burned domain overnight and does not replace a warm-up plan; what changes is that the risk on the IP and account is yours to see and manage, not a stranger's to create. License is $199 once, sending at roughly $0.10 per 1,000 emails, and it is not for you if you will not run an AWS account.