Dedicated IP vs Shared IP
Which SMTP approach is right for your email deliverability needs
The Fundamental Difference
The difference between dedicated and shared IPs comes down to one thing: whose reputation are you sending on?
Shared IP
Your emails go out from the same IP address as dozens or hundreds of other senders. You inherit their reputation—both good and bad.
Dedicated IP
You have sole control of an IP address. Your reputation is entirely your own. No one else's bad behavior can hurt you.
Head-to-Head Comparison
| Factor | Dedicated IP | Shared IP |
|---|---|---|
| Reputation Control | 100% yours | Shared with pool |
| Predictability | Consistent, own history | Can change overnight |
| Warmup Required | Yes, 28 days | No (already warmed) |
| Cost | Higher ($25-100/IP/month) | Lower (included in plans) |
| Setup Complexity | Higher (DIY warmup) | Lower (instant sending) |
| Blacklist Risk | Only your actions | Other senders can trigger |
| Volume Control | Full control | Limited |
| API Access | Full | Often restricted |
Shared IP: The Reality
How Shared Pools Work
Email providers aggregate senders into IP pools. High-volume senders with good reputations build pool reputation. Poor senders drag it down.
⚠️ The "Good Sender" Problem
Even if you're a perfect sender, you share the pool with everyone. If 50 spammers share your IP range, ISP filters flag the entire range—including you. You have zero control over this.
When Shared IP Makes Sense
- Transactional email only – Password resets, receipts, notifications
- Low volume – Under 1,000 emails/month
- Established relationships – Recipients already know you
- No cold email – No outreach to new recipients
The Shared IP Trap
Shared IP providers use reputation management to keep pool health up—but this means they restrict senders who violate thresholds. If you start getting good deliverability on shared IP and then scale up, you'll hit throttling. The provider's solution: upgrade to dedicated IP.
Dedicated IP: The Commitment
Own Your Reputation
With a dedicated IP, your sending history is yours alone. A perfect warmup means you control your reputation from day one.
✅ The Dedicated IP Advantage
Dedicated IPs are the only way to guarantee reputation isolation. If someone else's campaign triggers a blacklist, it has zero effect on your deliverability.
The Warmup Requirement
New dedicated IPs start with zero reputation. Sending too much too fast triggers ISP filters. A proper 28-day warmup is non-negotiable:
| Day | Safe Volume | Purpose |
|---|---|---|
| 1-7 | 100-500/day | Establish pattern |
| 8-14 | 500-2,000/day | Build initial trust |
| 15-21 | 2,000-10,000/day | Grow volume carefully |
| 22-28 | 10,000-25,000/day | Approach full capacity |
| 29+ | 25,000-50,000/day | Full warmup achieved |
When to Choose Each
Choose Shared IP If:
- You're sending transactional emails only
- Volume is under 5,000/month
- You're okay with average deliverability (85-90%)
- Budget is the primary constraint
- You don't need API access
- Recipients are existing customers only
Choose Dedicated IP If:
- You're doing cold email outreach
- Volume is above 10,000/month
- Deliverability above 95% is required
- You need predictable, consistent sending
- You're an agency managing client accounts
- API access and custom integration are needed
- You need reputation isolation for compliance
Cost Considerations
| Volume | Shared IP Cost | Dedicated IP Cost |
|---|---|---|
| 5K/month | $15-25/month | $40-60/month (wasteful) |
| 50K/month | $50-100/month (throttled) | $75-125/month |
| 200K/month | Not viable (throttled) | $150-250/month |
| 500K+/month | Not viable | $400-800/month |
The True Cost Calculation
Shared IP "appears" cheaper, but consider: at 50K/month you'll hit throttling and your effective deliverability drops to 60-70%. You're paying for emails that go to spam. Dedicated IP at higher cost but 97%+ deliverability often costs less per inbox delivered email.
CloudMails Approach
CloudMails includes dedicated IPs on all plans because we believe shared infrastructure is incompatible with professional cold email sending.
✅ Included on All Plans
- Dedicated IPs with every plan
- Automated 28-day warmup
- ISP-aware reputation monitoring
- Automatic rotation before thresholds