How to Choose Outbound Domains

If you're doing any kind of outbound work, sending cold emails is probably a significant part of your daily routine. You craft the perfect message, hit send, and…crickets. What happened?

Often, the problem isn't your sales pitch, believe it or not. Instead, it can stem from your email domain. If you're sending hundreds or even thousands of cold emails every week from your main company email address you're taking a huge risk that could accidentally land your whole company in spam folders.

But don't worry! Below, we'll clearly break down what you need to know about buying separate domains for cold outreach, why it matters, and how it can help you scale your cold email game — and we'll even give you tips on how to get to a point where you can send up to 100,000 emails per month, safely.

Why you shouldn't send emails from your main domain

When you send cold emails, recipients often mark them as spam — either because they're not interested, or because your email lands at a bad time.

Even if your emails are great, spam flags are inevitable. When too many spam reports happen, email providers (like Gmail and Outlook) label your entire domain as untrustworthy.

If you've been sending from your primary domain (e.g., yourcompany.com), this can cause all emails from your company; including crucial ones like invoices, newsletters, or direct communications with existing customers. to start landing in spam folders.

And trust me, digging your domain reputation out of spam is tough, expensive, and slow.

The good news? You can easily avoid this headache by purchasing dedicated outreach domains.

If you already know this, check out Instant Domain Search. We'll help you find and secure the perfect domains to protect your brand and ensure your emails reach the inbox.

What actually happens if your domain gets flagged?

Getting flagged as spam can happen faster than you'd think and it has immediate consequences for your sales outreach.

It's much easier (and cheaper) to protect it from the start rather than repair it after the damage is done.

What is a domain? A non-technical answer

Before we get into the complex stuff, let's go back to the basics.

If you're not sure what a "domain" actually means, no worries—you're not alone. Think of a domain as the digital address of your emails and website. It's what comes right after the "@" in your email address (for example: yourname@yourcompany.com).

When you're sending cold emails, you don't want to risk hurting your main brand's digital "home address." Instead, you'll want to use similar-looking (but separate) domains specifically for sales outreach. These are often variations of your main domain to keep your brand recognizable.

For instance, if your company's main domain is `yourcompany.com`, great outreach domain examples might be:

Noticed the non ".com" domains? If you'd like to learn more about domain extensions, we have a whole blog about this year's most popular domain extensions.

By having these separate domains, you're essentially creating safe, dedicated pathways for your outbound emails. Your recipients still recognize your brand, but your main business domain stays protected from any accidental damage.

How does getting more domains help you reach more people?

When it comes to sending cold emails at scale, one of your biggest challenges isn't just finding great prospects—it's getting your emails past spam filters and into your prospect's inbox.

Here's what you're really up against (and why it matters):

Every email provider (think Gmail, Outlook, Yahoo) uses complex algorithms to decide whether your emails land in someone's inbox or their spam folder. These algorithms analyze things like:

If you're sending hundreds or thousands of cold emails per day from a single domain, the chances of triggering these spam filters dramatically increase.

How multiple domains solve this problem:

Buying additional domains dedicated to cold email outreach allows you to strategically distribute your sending volumes across multiple trusted "digital identities."

Each domain maintains its own sender reputation independently, which significantly reduces your overall risk.

Here's exactly how having more domains helps you get your emails in front of more prospects:

Getting to 100k sends a month! How scaling with domains works

We are not joking, there are plenty of outreach specialists that are doing 50k, 100k, even 1Mil email sends a month. Don't believe us, check out some of the folks on reddit there are even communities around cold outreach.

Now, let's say you want to send 100,000 emails a month safely:

By scaling thoughtfully, you'll boost your reach without compromising deliverability. Your emails land exactly where you want them—in front of prospects.

Ready to start safely scaling your cold email outreach?

Head over to Instant Domain Search now to find and secure your dedicated cold-outreach domains today.

Quick setup list for non-techie folks

Now that you understand the importance of using separate outreach domains, here's your straightforward setup checklist:

For example:

However, be aware that some other email providers don't support multiple domains under one account. If your provider falls into this category, you'll have to create separate accounts for each new domain. This approach can quickly become complicated and harder to manage.

What Does "Warming Up Emails" Mean?

If you buy a new domain and immediately send thousands of emails per day, email providers see this as suspicious—like suddenly driving a brand-new car at 100 mph the moment you leave the dealership. To email providers, this looks like spam.

Instead, you need to gradually build up your sending volume. This is called "warming up" your emails, and here's how it works:

This careful approach shows email providers you're a legitimate sender, building a strong reputation. It's critical to achieving good email deliverability, ensuring your emails land safely in your prospects' inboxes rather than being lost to spam filters.

Explaining the tech stuff in more detail

These acronyms might sound intimidating, but they're just technical ways to confirm your emails are trustworthy:

Setting up these records significantly improves your emails' likelihood of landing in inboxes rather than spam. Typically, whoever manages your domain settings (like your IT or email admin) can handle this quickly for you.

Easy tips to avoid the spam filters

Spam filters can be tough but they're not unbeatable. Follow these straightforward guidelines to drastically reduce your risk:

To ensure your outreach stays effective, you need to regularly monitor your sending reputation and email performance. Here's how to stay proactive:

If you're looking for ways to scrub emails there are plenty of inexpensive providers that can help you with the outreach. But remember, your main priority should be to keep your primary domain as clean as possible, so make sure to start purchasing some domains.

Protect your brand and purchase more domains today

Get multiple domains today, use Instant Domain Search and our domain name generator to quickly find domains that sound similar to your already existing brand / primary domain. Avoid ending up in spam filters and hit that 100k emails a month mark. Good luck!