It’s not news that Mailgun can be unreliable for cold email. Mailgun relies heavily on shared IP pools by default, which means your deliverability is influenced by other senders. Mailgun is excellent for transactional email, but for cold outreach, shared IPs introduce serious risks. Even if you do everything right, like warm up safely, follow sending rules, and clean your list, another sender on your shared IP can damage the reputation you depend on. That’s why finding a strong Mailgun alternative is increasingly important for outbound teams. Aerosend is the Mailgun alternative built specifically for cold outreach at scale. Aerosend gives you fully isolated inbox clusters, aged IPs, automated rotation, premium warmup, and real-time domain health alerts. All of which removes the deliverability risks common with shared IP providers.
Why Aerosend Is Better Than Mailgun
Mailgun assigns most users to shared IPs by default unless they upgrade and warm up dedicated ones.
In cold email, shared IPs can cause sudden deliverability drops due to:
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Unknown senders abusing the same pool
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Spam complaints from others
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Poor list hygiene from another customer
Aerosend eliminates this risk entirely with:
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Private sending environments
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Aged dedicated IPs
For cold outreach, dedicated isolation is no longer optional. It’s required.
Scaling
Mailgun was built for transactional sending, not cold outbound. Scaling cold email safely requires:
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Isolated inbox clusters
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Dynamic IP rotation
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Domain rotation
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Real-time blacklist + reputation monitoring
Mailgun provides strong email API infrastructure, but does not provide rotation, clustering, or cold email-specific monitoring. Aerosend does.
Flexible pricing
Mailgun’s pricing increases quickly based on:
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Sending volume
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Validations
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Dedicated IPs
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Premium features
Aerosend offers simple monthly billing designed for outbound teams instead of transactional email pricing tiers.
Setup speed
Mailgun setup often requires:
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Manual DNS configuration
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Domain verification
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Optional warmup plans for dedicated IPs
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Custom routing setup
Aerosend configures everything automatically. Warmup, DNS records, and domain provisioning are done in minutes.
Responsive customer support
Mailgun offers ticket-based support; response times vary depending on plan level.
Aerosend provides:
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Fast responses
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Deliverability-trained support
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Hands-on help for domain health and cold outreach issues
Support matters when inboxing is on the line.
Premium warmup
Mailgun does offer automated IP warmup, but only for dedicated IPs and not for inbox-level warmup. Aerosend includes premium warmup for every inbox by default, optimized for cold outreach, something Mailgun is not built for.
Why Aerosend Is the Best Mailgun Alternative
Full isolation instead of shared IPs
Mailgun uses shared IP pools for most customers. Aerosend gives every user isolated sending to avoid shared reputation issues.
Faster setup
Mailgun requires manual DNS configuration. Aerosend provisions domains + mailboxes instantly with automated authentication.
Predictable performance
Mailgun’s shared pools make performance unpredictable for outbound senders. Aerosend’s isolated infrastructure ensures stable, consistent results.
Aerosend vs Mailgun: Cold Email Deliverability Comparison
| Feature | Aerosend | Mailgun |
|---|---|---|
| Primary Use Case | Built specifically for cold email outreach at scale | Built for transactional and API-based email |
| Cold Email Suitability | High. Designed for outbound teams and agencies | Low–Medium. Not optimized for cold outreach |
| IP Infrastructure | Dedicated, aged IPs with full isolation | Shared IP pools by default |
| Shared IP Risk | None. Private infrastructure per user | High. Other senders affect deliverability |
| Inbox Clustering | Yes. Isolated inbox clusters for safe scaling | No clustering model |
| Domain Rotation | Yes. Automated domain rotation | No |
| IP Rotation | Yes. Automatic and optimized for deliverability | Limited/manual |
| Premium Warmup | Included free for every inbox | Only available for dedicated IPs |
| Inbox-Level Warmup | Yes | No |
| Domain Burn Alerts | Yes. Real-time alerts when reputation drops | No |
| Blacklist Monitoring | Yes | Limited |
| Bounce & Reputation Tracking | Built-in, real-time | Not outbound-focused |
| Sending Scalability | High. Built for volume with safety | Limited for cold email |
| Setup & DNS Configuration | Fully automated (SPF, DKIM, DMARC, MX) | Manual DNS setup required |
| Domain Provisioning | Automated, optional | Manual |
| Sequencer Integrations | Smartlead, Instantly, Apollo | API-based only |
| Deliverability Predictability | High and stable | Unpredictable for cold email |
| Customer Support | Deliverability-trained, hands-on | Ticket-based, plan dependent |
| Pricing Model | Flat, outbound-focused monthly pricing | Volume + feature-based pricing |
| Best For | Cold email agencies, outbound teams, B2B sales | Transactional emails, app notifications |
How CallPad 4×’d Reply Rates by Fixing Deliverability
When Conrad, founder of CallPad, started running cold email, the problem wasn’t messaging, targeting, or offer. It was visibility. Emails were being sent, but many were never reaching the inbox. Deliverability, not conversion, was the real bottleneck. After switching to Aerosend, the impact was immediate and measurable. In controlled A/B tests, inboxes powered by Aerosend generated nearly 3× more replies than inboxes running on other providers.
As campaigns stabilized, reply rates moved from under 1% to 2–3% and eventually reached 4%. That improvement compounded quickly. Meeting volume increased by 3×, without changing copy, audience, or sending strategy. The only variable was infrastructure. CallPad helps small businesses, like salons and service providers, never miss a customer call or booking. With Aerosend handling deliverability, Conrad’s team now spends less time troubleshooting inbox issues and more time booking meetings for both CallPad and its clients.
The takeaway was simple: if you’re already paying for leads, software, and sequencing tools, inbox placement is the multiplier. Aerosend didn’t change what CallPad sent. It ensured the emails were actually seen.
How to Set Up Aerosend as Your Mailgun Alternative
1. Add your domains: Bring up to 30 domains.
2. Create isolated inbox clusters: 3 inboxes per cluster, fully separated.
3. Authenticate automatically: SPF, DKIM, DMARC, MX. Instant setup.
4. Start premium warmup: Included free for every inbox.
5. Connect your sequencer: Smartlead, Instantly, Apollo, etc.
6. Track performance: Bounce rates, blacklist entries, domain burn alerts.
