Dedicated IP or shared pool? Choose by volume, not by vanity
A dedicated IP means owning your reputation alone — which is only an upgrade if you send enough to sustain one. The honest thresholds.
Infrastructure · 3 min read · updated
What you are actually choosing
Sending reputation attaches to IPs (and domains). On a shared pool, your mail rides on a reputation built by every sender in the pool; on a dedicated IP, the reputation is yours alone — built by you, damaged only by you, and maintained only by you.
"Dedicated" sounds like the premium option, and providers price it like one. But reputation is fed by volume: providers only trust a pattern they can observe, and an IP that sends too little or too irregularly never gives them one. Below a volume floor, the premium option delivers worse.
The volume floor
As a working rule, a dedicated IP wants something in the region of 100,000+ messages a month, sent steadily — roughly a few thousand a day — to keep its reputation warm and legible. Well below that, each send arrives from an IP the provider has half-forgotten, which is a mild cold start every time.
Steadiness matters as much as the total. A million messages on the first of each month and silence in between is a worse pattern than a tenth of the volume spread evenly.
When dedicated genuinely wins
- You clear the floor comfortably. High, steady volume gives you full control of a reputation big enough to be robust — and isolates you from ever sharing consequences with a stranger's bad day.
- You cannot afford neighbours. Compliance-sensitive mail, or simply mail important enough that "another tenant got the pool throttled" is an unacceptable sentence in a postmortem.
- You want your history portable and legible. A dedicated IP's track record is unambiguously yours — useful when negotiating with providers, debugging placement, or proving your standing.
When the shared pool wins
- Low or spiky volume. The pool's reputation is maintained by the aggregate, so your occasional newsletter inherits a warm, active history it could never sustain alone.
- Day one. A new sender on a dedicated IP starts from zero and must warm up before doing anything. On a managed pool, useful volume flows immediately.
- The pool is actually policed. The shared-pool horror stories come from providers who let anyone in. A pool with real entry standards and active eviction is a well-kept neighbourhood — the quality of the landlord is the real variable, not shared-versus-dedicated.
The sensible path
Start shared. When your steady volume clears the floor and your metrics are clean, add a dedicated IP and warm it properly while the pool carries the remainder — then migrate stream by stream, transactional last. Running both during the transition is normal, not a compromise.
And remember the domain carries reputation too: a dedicated IP is not a fresh start after a damaged sending history, because the domain's record follows you onto it.
Common questions
Does a dedicated IP improve deliverability?
Above the volume floor, with clean practices — usually yes, through control and isolation. Below the floor it commonly makes placement worse than a good shared pool. The IP type is an amplifier of your sending pattern, not a fix for it.
Should transactional and marketing mail share a dedicated IP?
Separate them — different subdomains at minimum, separate IPs once volume justifies it, so a campaign mistake can never spam-folder your password resets.
Do I ever need more than one dedicated IP?
At very high volumes, extra IPs add throughput headroom and stream isolation. Adding IPs to dilute a bad reputation, however, is a known spammer pattern — providers watch for it, and it makes things worse.
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