Free Domain Variations
for Cold Email

Generate clean, brand safe domain variations for cold email instantly.
Rotate domains and improve deliverability. Just with one click.

Just 2 simple steps to get your domains

Enter your main domain name and select the number of domains you want. Click on next.

Purchase these domains from Godaddy or Porkbun. Use the provider that you prefer

Create an Aerosend account to get inboxes for your domains and start sending.

Why use a domain variation tool?

You need domains that sound like your brand for cold email. That is the only way to be successful at cold email.

If you’re reading this, you probably already know better than to blast from your main domain. Perhaps what you didn’t know is that not all cold email domains are the same. Some can get your deliverability to 0, while others might perform well. It all comes down to how effectively you use them.

No worries, though. This blog will take you through everything you need to know and more. By the end, you’ll know how domain variations for cold email protect deliverability, what types to use, what mistakes to avoid, and how top senders scale with multiple email domains in rotation.

How Domain Variations Protect Your Deliverability

In case you missed it, the primary purpose of getting domain variation for cold email is to allow you to scale your campaigns safely and maintain domain health in the process.

Why? Because using just one cold email domain puts your entire outreach at risk. If it loses its reputation, its deliverability stops. So, if you ask any cold emailer who does it at scale (Hello, it’s us), they’ll tell you that they use multiple domain variations for cold email to distribute volume and reduce exposure to risks like spam filters.

Types of Domain Variations That Work

Choosing the right domain variations for cold email can make or break your deliverability. You need domains that look trustworthy and avoid red flags.

Prefixes/suffixes:
- Main Domain: Brand.com → hellobrand.com, trybrand.com, sendbrand.net, heybrand.io
TLD swaps:
- Good: .com, .net, .io, or .co
- Bad: xyz, .top, .ml, .ga, .ai
Intent-based domains: contactbrand.com, getbrand.io, joinbrand.net

How Many Domains Do You Really Need?

Maintaining deliverability and testing it requires you to have multiple cold email domains in rotation. Start with at least 10. Just enough to spread volume and isolate issues.

Each domain should handle no more than ~75 emails/day to stay under the radar. Cold emailing requires volume to test messaging; you need to send at least 2,000 emails to validate a campaign*.*

For example, 50 domains give you 3,750 sends/day without risking reputation.

Quick breakdown:

1 domain = 3 inboxes
Max 25 emails/inbox/day
3 inboxes × 25 = 75 emails/day/domain
10 domains = 750 emails/day
50 domains = 3750 emails/day

Step-By-Step: How To Set Up Domain Variations For Cold Email

Once you are happy with the domain variations you’ve picked for your cold emails, here’s how to see them in action:

1. Register The Domains

2. Get Your Inboxes

Once you’ve got your domain variations in order, you’re going to need inboxes to start sending emails. You can manually pick providers and register them one by one, or you could pick a tool like Aerosend to get an entire inbox infrastructure that takes care of everything from authentication to warming up and maintaining domain health. It’s built for cold emailers.

3. Email Authentication

A reminder: Do not forget to authenticate your email. This is what keeps your domains from spam filtering. A little brush-up on what you need to do:

SPF: The Sender Policy Framework will decide which mail servers have the authorization to send emails from your domain.
DKIM: Domain Keys Identified Mail will ensure that your emails do not get messed up during transit.
DMARC: Domain-based Message Authentication, Reporting & Conformance will protect your email against all attacks.

Note: Authenticating emails can be too technical for some, but Aerosend does this for you automatically. Just buy your domains and leave the rest to us.

4. Warmup Each Domain

All domains need to be warmed up for at least 3-4 weeks. Aerosend uses Warmupinbox for all their clients (It’s complimentary!). You need to establish trust as a new domain and even for the older ones, so make sure that ALL your domains are being warmed up consistently.

5. Start Sending Emails

Manually sending cold emails is a nightmare. Get a sequencer like Smartlead and automate the process.

Advanced Cold Email Tip: Use Sine Wave Pattern for email sending

So, if you have 10 domains, ready for use after warmup, you will have two sets of 5 each. From there, you will use the first set to send emails for two weeks, while the other one is also being warmed up. Then, you will switch it out after the two weeks are up. So on and so forth. This way, you can maintain the health of your domain without it burning up.
You use 10 domains → 2 sets → 5 domains each
Use the first 5 to send emails for two weeks → The second set is still under warm-up with the first one
Stop sending from set 1 after two weeks → Switch to set 2 → Repeat

6. Monitor Deliverability

What you can do next is monitor your deliverability. Of course, there is no absolute way to know where your email eventually lands. However, there are signs you can look for.

Warm up: Since all your inboxes are in constant warmup, keep your eye on the results. Ideally, your warmup score should be 100%. Anything less is a cause for concern.
Inbox placement: The experts at Aerosend conduct an inbox placement test bi-weekly for our clients to make sure that our emails land in the primary inbox and not the spam folder.
Bounce Types and Rates: If your emails are getting bounced, then it’s time to look at the root cause of the situation. There could be two: Your lead list or your domain. If you think your domain is healthy, it is time to get a new lead list. If you think it isn’t your lead list, check your domain health. The bad ones need to be deleted. Additionally, bounce rates should always be below 0.01%.
Reply Rates: A good reply rate can be difficult to maintain, but if you do everything right, and the reply rates still drop? Have a good look at your campaign, break down everything by domain to isolate the issues. Get rid of the worst-performing ones.

Mistakes to Avoid While Picking Domain Variations for Cold Email

Like everything, there are certain things you should steer clear of. Especially while picking domain variations for cold emailing. Here are just a few:

Sending Too Many Emails from One Domain

If you consistently send emails from a single domain or even two, you’re gonna burn it. You need to rotate domains and try different ones to land in the inbox. Also, if your single domain gets reported, you won’t have any options to fall back to.

Consistently Ignoring Useful Metrics

If you’re rotating domains and taking the steps to ensure that they’re healthy, but still see no engagement, it is a clear sign that your domains may not be working. It’s best to check your deliverability reports in this case. This way, you can monitor that your emails are landing where you actually want them to.

Sending Generic Emails in Bulk

Mass sending is never a good idea. This is because blanket emails get reported the most. What you need to do is target your audience well and have a message that is catered specifically to them. Maintaining this will not only help your outreach but also your overall domain health.

How to Use Domain Rotation for Cold Emailing Effectively (Straight From the Experts)

Buying the right domain is only half the game. It is using them right that lands you and keeps you in the inbox. Let’s learn how to structure and manage your domain variations for cold email to maximize deliverability.

Pick your Inbox Provider Carefully

You don’t want to pick just any inbox provider when it comes to sending cold emails. Preferably pick one that is specifically built for cold emails…like Aerosend.

Use 3 Inboxes Per Domain

Our experts recommend not using more than three inboxes per domain to reduce risk and evenly distribute volume. This keeps sending volume low per domain (75 emails/day) and protects your domain reputation

Have a Healthy Pool of Providers

To rotate domains effectively, you need to have multiple providers. If one provider has a sudden algorithm shift, you need to have a backup. Distribute your domain variations for cold email across 2–3 providers to have options at hand.

Or you can simply use a provider like Aerosend that is specially built for cold emailers. Here, there are no random algorithm changes and bans. You’re always in the loop and work directly with industry experts.

Replace Cold Email Domain If Burned

If a domain is dead, there is no point in reviving it. Retire it and replace it with a fresh variation. Warming up a new domain is faster and safer than trying to rebuild trust in a burned one. Using your domain variations for cold email this way helps you stay scalable and well below the radar of spam filters.

Frequently Asked Questions

Why are domain variations for cold email important?

It protects your main domain. Rotating domains will increase your chances of landing in the inbox and lessen your chances of getting blacklisted.

What are the best domain variations for cold email?

Use domains that sound like the main domain. Add prefix/suffix like get, try, hello to the brand. Use ".com" domains with no numbers and special characters.
You can also avoid all the work. Our free tool filters out spammy options and gives you the best domain names for cold email.

Isn’t one .com domain enough?

No, it is not. Once it gets flagged or spam-rated, your reply rates drop, and every email you send suffers. Multiple cold email domains spread the load and reduce the risk of getting blacklisted.

What if I use my main domain to send cold emails?

You’ll burn it. If not immediately, then eventually. Even a single campaign that results in spam complaints or high bounce rates can trash your sender reputation. Save your main domain for warm conversations and use separate domains for outbound.

I have multiple domains, now what?

Now you need to create inboxes. After testing every single combination of email provider, we recommend Aerosend.io to create your inboxes. It is the only provider suited for cold email.

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