How Many Domains Do You Need for Cold Email?

To run successful cold email campaigns, you need to carefully manage your domains to protect your sender reputation and ensure high deliverability. Here’s the short answer:

• Use multiple domains (2–3 for most businesses) to spread the risk of blacklisting and scale your outreach safely.
• Start small: Send a low volume of emails (20–50 per day) per domain and gradually increase as the domain warms up.
• Avoid using your primary domain for cold emails to protect your business communications from being flagged.
• Monitor daily sending limits of your Email Service Provider (ESP). For example, Google Workspace allows 2,000 emails per day, while free Gmail accounts cap at 500.
• Keep spam rates below 0.1% to maintain a good domain reputation.

Quick Tip: For higher volumes (e.g., sending 6,000 emails/day), divide the workload across multiple domains and inboxes. This ensures you stay within ESP limits and maintain deliverability.

Quick Comparison

For most businesses, three domains provide the right balance between scalability and safety. Start small, monitor performance, and scale responsibly to avoid deliverability issues.

What Determines How Many Domains You Need

The number of domains you should use for cold email outreach depends on several factors that directly influence your campaign's performance and email reputation.

Daily Email Volume

Your daily email sending volume plays a major role in deciding how many domains you'll need. Sending too many emails from a single domain can lead to spam filters flagging your messages or even account suspensions. If you exceed the daily sending limits of your email service provider (ESP), additional domains become necessary.

By using multiple domains, you can distribute your email load, effectively multiplying your sending capacity. For instance, if you're using Google Workspace and need to send 6,000 emails per day, you’d need at least three domains to stay within the 2,000-email limit per domain. For newer domains - those less than three months old - it's wise to start small, sending only 20 to 50 emails daily and gradually increasing the volume to establish a solid reputation.

Interestingly, about 8% of salespeople send more than 50 cold emails daily, while nearly 40% of professionals find sending just 5–10 cold emails per day to be the most effective approach. For many businesses, starting with a single, well-managed domain may be sufficient, at least initially.

But beyond volume, the reputation of each domain is key to ensuring your emails actually reach inboxes.

Deliverability and Reputation Management

Every domain builds its own reputation with ESPs over time. Relying on a single domain for all your cold emails can be risky. Statistics show that around 80% of cold emails are never opened, and nearly half of the 347 billion emails sent daily are categorized as spam. Using multiple domains can help spread the risk of blacklisting or penalties, which could otherwise cripple your outreach efforts.

By warming up each domain individually, you not only improve deliverability but also reduce the likelihood of being flagged by ESPs. This strategy ensures that even if one domain faces issues, your overall campaign can continue running smoothly.

Risk Mitigation

Relying on a single domain for cold outreach is a gamble. If that domain gets flagged, your entire campaign could grind to a halt. Over time, even well-managed domains can lose reputation, which is why savvy email marketers cycle through domains. When a domain shows signs of decline, it’s retired before it harms the overall sender reputation. Having backup inboxes ready allows you to quickly replace flagged domains, ensuring minimal disruption to your outreach.

Using multiple domains also gives you the flexibility to experiment. You can test different subject lines, email templates, or sending schedules without putting your primary domain’s reputation at risk. This approach not only keeps your campaigns running but also allows room for growth and optimization.

Domain Usage Approaches for Cold Email Campaigns

When planning a cold email outreach strategy, there are two main ways to manage your domains. Each method comes with its own set of benefits and challenges, depending on your email volume and business objectives. Let’s break them down.

Single-Domain Approach

The single-domain approach works best for those sending fewer than 40 emails per day. It’s straightforward to manage, with a single reputation profile to monitor and streamlined authentication processes. This simplicity makes it ideal for low-volume senders. However, there’s a significant downside: if your domain’s reputation takes a hit - such as being flagged - it can take weeks to recover. During that time, your campaigns may grind to a halt, creating a serious bottleneck for your outreach efforts.

Additionally, this approach limits your flexibility. You can’t test riskier strategies without potentially harming your domain’s reputation, making it harder to experiment and optimize your campaigns.

Multi-Domain Approach

For businesses with higher email volumes or a need for more flexibility, the multi-domain strategy is a better fit. Typically, this involves using 2–3 domains, each with its own mailbox. This setup allows you to send up to 90 emails daily (30 per domain), significantly increasing your outreach capacity.

The biggest advantage here is risk management. As email marketing expert Arpit Mishra puts it:

"Multiple domains provide a safeguard against the risks of blacklisting and allow for more experimental marketing tactics."

If one domain encounters issues, the others can keep your campaigns running, ensuring continuity. This strategy also offers more granular control - you can assign specific domains to different customer segments, products, or campaigns. This not only simplifies performance tracking but also helps fine-tune your strategies.

For most businesses, three domains strike the right balance between scalability and manageability. Larger setups - like those used by specialized cold email agencies - may require more, but for most, starting small and scaling as needed is the way to go.

If you choose the multi-domain approach, remember to warm up each domain gradually and ensure proper authentication settings are in place. While this method demands more technical expertise and ongoing effort, the payoff is significant: better deliverability, reduced risks, and the ability to scale your campaigns effectively. This sets the stage for further discussions on expanding domain usage in the next section.

How to Scale Your Cold Email Outreach with More Domains

Scaling cold email campaigns takes more than just increasing the number of emails you send. It’s about expanding your reach while keeping your deliverability intact. Here’s how you can do it effectively.

When to Add More Domains

You’ll know it’s time to add more domains when you’re consistently hitting your daily sending limits. But volume isn’t the only factor to consider. Look out for these signs:

• If you’re regularly reaching your email volume cap or notice a drop in deliverability, it’s time to bring in additional domains. Keeping an eye on your Email Service Provider (ESP) limits can help you avoid triggering spam filters.
• Running separate campaigns? Using dedicated domains for each campaign can help isolate risks and protect your overall deliverability.
• Relying on just a few domains can be risky. If one gets blacklisted during a crucial campaign, your outreach efforts could grind to a halt.

Once you’ve determined that you need more domains, it’s important to integrate them carefully to avoid disruptions.

How to Scale Properly

Adding new domains isn’t something you can rush. A gradual approach ensures each domain is properly set up and warmed up before you scale. Here’s a step-by-step guide:

• Start small: Add one or two domains at a time. This makes it easier to manage and monitor their performance.
• Warm up gradually: Follow a structured warm-up schedule to build trust with email providers:
  • Week 1: Send 5–10 emails per day per new inbox
  • Week 2: Increase to 15–20 emails per day
  • Week 3: Increase to 30–50 emails per day
  • Week 4 and beyond: Cap at 50 emails per inbox daily
• Monitor performance: Keep an eye on open rates and complaints. If a domain starts showing poor results, consider retiring it to protect your overall deliverability.

For a smoother process, automated tools like Primeforge can be a lifesaver. They handle tasks like domain warm-up and DNS management, including configuring DMARC, SPF, and DKIM records. With features like bulk DNS updates, managing multiple domains becomes much easier, saving you time and reducing the chance of errors.

Rahul Lakhaney, Former VP at Gartner and now CEO of Enrich.so and Maximise, shares his insights on scaling email infrastructure:

"I've been using a couple of other email infra forges for over a year and have been pretty impressed with deliverability. Now I added Google mailboxes and been using them for months as one of the early adopters to spread the load of 10K+ emails/day over to more ESPs. Stellar deliverability on Salesforge and spam tests always come back green! Excited to spin up some Outlook accounts soon also."

Using multiple ESPs, such as Google Workspace and Microsoft 365, can further enhance deliverability. Separating domains by client, campaign, or team can help you stay organized and maintain control as you scale your outreach.

In the long run, a thoughtful approach to domain scaling ensures better deliverability, reduces risks, and keeps your campaigns running smoothly - even if one domain faces issues.

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Tools for Managing Multiple Domains

Handling multiple domains manually can become a logistical nightmare, especially when scaling cold email campaigns. Thankfully, tools like Primeforge make the process much more manageable by reducing setup time and simplifying technical tasks. Proper domain management is essential for ensuring high email deliverability and safeguarding your outreach reputation.

Primeforge: A Solution for Cold Email Infrastructure

Primeforge is a purpose-built platform tailored for managing cold email infrastructure. Unlike standard email services, it caters specifically to the demands of cold outreach. It combines Google Workspace and Microsoft 365 mailboxes with US-based IP addresses, boosting email deliverability rates. One of its standout features is the automated DNS setup, which simplifies configuring DMARC, SPF, and DKIM records. Additionally, its bulk DNS update feature lets you manage DNS records for all your domains from a single, user-friendly dashboard.

With multiple workspaces, you can easily organize domains based on clients, campaigns, or teams. On the cost front, Primeforge offers mailboxes at $3.50–$4.50 per month, saving up to 46% compared to Google Workspace and 25% compared to Microsoft 365. As part of the Forge Ecosystem, which includes Mailforge for shared email infrastructure and Infraforge for private configurations, Primeforge delivers flexible options to suit various scales and requirements.

Manual Setup vs. Automated Solutions

The advantages of automation become even clearer when compared to manual domain management. Setting up domains manually not only takes more time but also requires advanced technical skills. Automated tools like Primeforge eliminate errors that could negatively impact email deliverability.

Conclusion: Choosing the Right Domain Setup for Your Cold Email Campaigns

Your domain setup plays a critical role in the success of your cold email campaigns. The number of domains you use should align with your email volume, deliverability goals, and risk management strategy. For most businesses, three domains strike the right balance - allowing for about 90 emails per day while maintaining a solid sender reputation.

Using multiple domains safeguards your primary domain, minimizes the risk of blacklisting, and helps isolate potential campaign issues. By spreading your email volume across several domains, you avoid overloading any single domain and maintain a healthy sender reputation. Since Outlook and G Suite dominate the email landscape, accounting for over 80% of email addresses, optimizing your deliverability with these providers is key.

Start small - send emails in low volumes and gradually build each domain's reputation before scaling. Keep a close eye on your open and reply rates; if you notice a drop, adjust your strategy before adding more domains. Tools like Primeforge can simplify domain management, offering quick setup and bulk updates, which become essential as your outreach scales.

For most businesses, expanding beyond three domains is unnecessary unless you’re operating as a cold email lead generation agency. Instead of immediately adding more domains, focus on improving your messaging and ensuring your authentication records (SPF, DKIM, DMARC) are correctly configured. Continuously refining your campaigns is key to maintaining strong engagement rates.

Automated tools make it easier to transition from a smaller setup to a robust multi-domain strategy. For those just starting out, three properly warmed domains with gradual increases in email volume provide a solid starting point. As your campaigns grow, automation helps you scale efficiently while avoiding technical headaches.

Following these principles ensures your domain strategy supports both deliverability and scalable, successful cold email outreach.

FAQs

What’s the best way to warm up a new domain for cold email outreach?

To effectively warm up a new domain for cold email campaigns and maintain strong deliverability, start small. Begin by sending just 5 to 10 emails per day and gradually increase the volume by 10–15% daily. For the first few weeks, keep your daily email count between 10 and 50. This slow, steady approach helps establish a solid sender reputation.

Ensure your domain is authenticated with SPF, DKIM, and DMARC protocols. These settings enhance the legitimacy of your emails and reduce the risk of them being flagged as spam. Focus on crafting high-quality, personalized emails for recipients who are likely to engage. Positive interactions - like opens and replies - boost your sender reputation. Avoid using spammy language, and stick to clear, professional communication to keep your emails out of spam folders.

For a streamlined way to manage your cold email setup, consider Primeforge. They provide solutions like automated DNS configuration and US-based IP addresses, making it easier to handle your outreach campaigns efficiently.

What are the risks of using just one domain for cold email outreach, and how can you avoid them?

When you use just one domain for cold email outreach, you risk damaging its reputation if recipients mark your emails as spam or block them. This could even lead to your domain being blacklisted, which would disrupt your ability to send emails - including critical business communications.

To steer clear of these issues, it’s smarter to set up a dedicated domain exclusively for cold email campaigns. This approach protects your primary domain’s reputation and ensures it remains unaffected. Plus, a separate domain can help improve email deliverability, keeping your main business operations running smoothly.

How do I know when to add more domains to my cold email strategy?

If you're running into problems like declining email deliverability, your messages landing in spam folders, or even worse, your domain getting blacklisted, it might be time to consider adding more domains to your cold email strategy. These issues are strong indicators that your current domain's reputation is taking a hit, which could seriously undermine your outreach efforts.

Expanding the number of domains you use becomes even more critical as your campaigns grow. By using multiple domains, you can safeguard the reputation of your primary domain while maintaining strong email performance. For businesses sending a large volume of emails or scaling their outreach, diversifying domains helps minimize risks and boosts overall deliverability.

To simplify this process, platforms like Primeforge offer solutions tailored to cold email campaigns. Their tools include automated DNS setup and US-based IP addresses, making it easier to manage and scale your email efforts without compromising on performance.

Related posts

• 7 Ways to Improve Cold Email Deliverability Rates
• How to Scale Mailboxes for Cold Email Campaigns
• Scaling Outreach with Multiple Mailboxes
• Why Should You Diversify Your Cold Email Infrastructure