· 8 min read
Dedicated vs shared IP: the real decision
Dedicated IPs are often pitched as an upgrade. They're actually a trade. You get isolation from other senders' reputation — including their bad days. You also own the reputation entirely, which means a bad week on your side isn't absorbed by the pool. For most lifecycle programs, the shared pool is the better default. For some, dedicated is the only option. Here's how to tell which you are.
Justin Williames
Founder, Orbit · 10+ years in lifecycle marketing
What each one actually is
Shared IP pool: your ESP (Braze, SendGrid, Mailgun) sends your mail from IPs that handle thousands of other senders. Your reputation is partly your own, partly inherited from the pool average. A bad day across the pool raises your delivery risk; a great week across the pool helps yours.
Dedicated IP: an IP that sends only your mail. Your reputation is 100% yours. No other sender can affect it — for better or worse. Requires a warm-up period before you can send at full volume (covered in the IP warm-up playbook), and requires sustained volume to maintain trust.
The volume threshold almost nobody hits
A dedicated IP that sends 10,000 emails a day has worse deliverability than a shared pool that sends 10 million. Volume is what sustains reputation.
The rule of thumb: you need to sustain 100,000+ emails per day, every day, before a dedicated IP outperforms a well-run shared pool. Below that volume, ISPs can't build a reliable signal from your sending patterns, and you end up with an IP that's technically dedicated to you but treated as unfamiliar every time you send.
Some teams hit volume requirements on peak days but fall below them on quieter days. That's worse than low volume consistently — ISPs watch for volume variance, and inconsistent senders are treated as riskier than consistent low-volume senders. If your program sends 200K on Tuesdays but 20K on Fridays, you're not a candidate for a dedicated IP until the volume floor comes up.
The risks dedicated IP introduces
Cliff risk. A bad campaign (high complaint rate, unusually high bounces) damages your sole-owned reputation directly. On a shared pool, the pool absorbs some of the variance; on a dedicated, it hits you full force. Recovery typically takes 3–6 weeks.
Warm-up time cost.A new dedicated IP can't send at full volume from day one. The warm-up is 2–4 weeks of managed volume increase. If you urgently need to migrate sending, you're not actually moving on day one — you're starting a month-long transition.
Monitoring overhead.You need to actively watch reputation (Google Postmaster Tools, Microsoft SNDS, your ESP's deliverability reports) because you're the only sender on that IP. On a shared pool your ESP does most of this for you.
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When dedicated is genuinely the right call
Three contexts where dedicated IP is the right answer even at lower volume:
Regulated sending. Financial services, healthcare, any program with legal requirements around message integrity. The isolation matters because a shared pool incident could technically be attributed to you.
Highly-variable sending profile. Transactional-only services that need near-100% deliverability (password resets, order confirmations) benefit from a dedicated IP because their sending pattern is consistent and high-engagement, which builds excellent reputation cleanly.
Enterprise recipient base. B2B programs sending into corporate Microsoft Exchange servers benefit from the predictable reputation of a dedicated IP because corporate filters tend to whitelist known senders.
The middle path most programs overlook
Split sending: marketing mail on the shared pool (benefits from pool reputation, absorbs occasional bad days), transactional mail on a dedicated IP (consistent, high-engagement, builds excellent reputation). Requires two separate ESP configurations and usually a subdomain split (mail.brand.com for marketing, notify.brand.com for transactional).
This is the architecture larger programs end up on anyway after a few years of painful deliverability incidents. Starting there saves the incidents. The Orbit Deliverability Management skill covers the full domain + IP split pattern including subdomain setup, SPF/DKIM/DMARC configuration per subdomain, and monitoring across both streams.
Frequently asked questions
- At what volume should I switch to a dedicated IP?
- 100,000+ sends per day, every day, as a baseline. Below that volume ISPs can't build a reliable reputation signal and the dedicated IP underperforms a shared pool. Spiky volume (huge peaks, low floors) is also a sign to stay shared.
- Is a dedicated IP automatically better for deliverability?
- No. Volume-starved dedicated IPs often deliver worse than shared pools. Dedicated is a trade: isolation in exchange for higher-volume requirements and more operational overhead. For most programs, the shared pool is the better default.
- How long does it take to warm up a new dedicated IP?
- 2–4 weeks depending on target volume. The IP warm-up playbook covers the exact ramp schedule. You can't send at full volume from day one; plan the transition across a month, not a weekend.
- Can I run marketing on shared and transactional on dedicated?
- Yes — this is the middle path most mature programs adopt. Marketing on shared benefits from pool reputation; transactional on dedicated builds excellent reputation from consistent high-engagement sending. Requires separate subdomains and authentication setup for each.
- What happens if my dedicated IP reputation collapses?
- Expect 3–6 weeks to recover. Immediately scale back volume to highest-engagement segments only, diagnose the cause (volume spike, complaint surge, authentication failure), and don't return to normal volume until reputation signals in Postmaster Tools and SNDS recover. In severe cases you may need to request a new IP from your ESP.
- Does Braze charge extra for dedicated IPs?
- Typically yes, and the cost scales with the number of IPs. Confirm pricing before committing — a dedicated IP that costs thousands per year and underperforms the shared pool is a losing trade.
This guide is backed by an Orbit skill
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