Dedicated IP vs Shared: When It is Actually Worth It
A dedicated IP costs more, takes weeks to warm up and can hurt you if you do not have the volume to feed it. Here is the honest decision framework.
"Should I get a dedicated IP?" is the single most common deliverability question we get. The honest answer is: probably not yet. A dedicated IP is a deliverability tool, not a status symbol, and using it correctly requires consistent volume, careful warm-up, and active reputation management. Get any of those wrong and a dedicated IP will deliver worse than the shared pool you came from.
This article gives you the actual decision framework: when shared is the right choice, when dedicated wins, what warm-up really looks like, and how the major providers (SendGrid, AWS SES, Postmark, Mailgun, Target) compare in practice.
What Shared IPs Actually Are
On a shared IP pool, your mail leaves from one of a hundred or so IPs along with traffic from many other senders. Receivers compute reputation on the IP. So your reputation is the weighted average of everyone sharing the pool with you, weighted by volume.
This sounds bad. In practice, reputable providers curate their pools aggressively: they reject high-risk customers, suspend abusers within minutes, and segment pools by traffic type (transactional vs marketing vs cold). A well-curated shared pool will outperform 80% of self-managed dedicated IPs.
What Dedicated IPs Actually Are
A dedicated IP is one address only your domain sends from. Reputation is yours, entirely. The upside: you get the credit for your good behaviour. The downside: you get all the blame for the bad. There is no buffer.
Critically, a brand-new dedicated IP has zero reputation. Receivers do not know you. They will rate-limit aggressively, route to spam, or outright reject. Climbing out of that hole takes 4-8 weeks of careful warm-up.
The Volume Threshold
For dedicated to pay off, you need to ship enough mail that receivers can meaningfully compute reputation. The rough threshold is:
- Below 50,000 emails/month: definitely shared.
- 50,000 to 200,000 per month: shared still wins for most use cases.
- 200,000 to 1,000,000 per month: dedicated starts to pay off, especially if mostly transactional.
- Above 1,000,000 per month: dedicated almost always wins; consider multiple IPs (one per stream).
⚠️ Warning: If your volume is below the threshold, your dedicated IP will look "idle" to receivers and they will assume new = suspicious. Idle reputation is worse than shared.
The Warm-Up Process
Warming up a new IP means gradually increasing volume so receivers see a predictable pattern and assign reputation. A typical schedule:
| Day | Max sends/day (Gmail) | Max sends/day (Outlook) |
|---|---|---|
| 1-3 | 50 | 50 |
| 4-7 | 500 | 200 |
| 8-14 | 2,000 | 1,000 |
| 15-21 | 10,000 | 5,000 |
| 22-30 | 40,000 | 20,000 |
| 30+ | Full | Full |
The numbers double roughly every 3-4 days. Send your most engaged recipients first — opens and clicks build reputation faster than untouched mail.
The Multi-IP Strategy
Once you are past 1M/month, splitting traffic by type matters more than total volume. Run three streams:
- IP 1: transactional (receipts, password resets). High engagement, low complaint rate. Reputation goldmine.
- IP 2: marketing/digests. Lower engagement, higher complaint rate. Isolate so it cannot drag transactional down.
- IP 3: re-engagement / cold. Highest risk. Isolate so it cannot drag anything.
The key insight: receivers compute reputation per IP. If you do not segment, your cold re-engagement campaign tanks your password reset deliverability.
When Shared Wins
- Volume below 200k/month.
- Spiky traffic (you ship 100k in one day, nothing for two weeks).
- No-one on the team owns deliverability operationally.
- You are still validating product-market fit.
When Dedicated Wins
- Steady volume above 500k/month.
- You ship sensitive transactional mail and cannot afford a noisy neighbour incident.
- You can dedicate at least 4 hours/month to reputation monitoring.
- You ship multiple traffic types and want to isolate them.
The Hidden Cost
The price difference between shared and dedicated is usually 50-150 EUR/month. The hidden cost is operational: someone must monitor reputation, blacklists, warm-up adherence, per-receiver throttling. Without that ongoing attention a dedicated IP is just a slow-motion deliverability incident.
Per-Provider Notes
SendGrid
Dedicated IPs available from Pro plan up. Warm-up tool included but conservative; manual override possible. Shared pools are large and somewhat noisy.
AWS SES
Dedicated IPs as add-on, $24.95/month/IP. Warm-up is fully manual — you set the daily cap. Shared pool is enormous but you have no SLA on it.
Postmark
Premium plans include a dedicated IP, others use a tightly curated transactional shared pool that often beats raw dedicated for typical SaaS.
Mailgun
Dedicated IPs included from Foundation plan. Excellent for high-volume but requires self-managed reputation.
Target SMTP
Shared pools curated per traffic type (transactional, marketing, cold). Dedicated IP available with automatic warm-up enforced by the Send-Time Firewall — the firewall actually blocks sends that would exceed the daily cap, preventing accidental warm-up violations.
The Honest Recommendation
Start on shared. Move to dedicated only when (a) your monthly volume justifies it, (b) you have a stable engagement pattern, and (c) someone on your team will own reputation monthly. If any of those is missing, save your money and your inbox placement.
If you do go dedicated, ask your provider whether warm-up is enforced or merely suggested. Suggested warm-up plans get violated by accident every release cycle. Enforced ones — like the cap in the Target SMTP Send-Time Firewall — make the warm-up actually happen.