Scaling Cold Email: From 100 to 10,000 Sends

Scaling a cold email campaign from 100 to 10,000 sends is achievable with the right strategy. Here’s the quick version:

1. Set Up Infrastructure: Use separate domains for outreach and authenticate them with SPF, DKIM, and DMARC.
2. Warm Up Gradually: Start with 10-20 emails/day per account and scale over 30 days to build a strong sender reputation.
3. Maintain Deliverability:
   • Limit sends to 200-300/day per domain.
   • Clean your email list regularly to remove invalid or inactive addresses.
   • Monitor key metrics (e.g., open rates > 60%, bounce rates < 5%, spam complaints < 0.1%).
4. Use Multiple Mailboxes: Spread sending across accounts and stagger times to mimic natural behavior.
5. Automate & Personalize: Use tools to manage email sequences, personalize content, and track responses.

Key Tip: Quality matters more than quantity. Use targeted data and follow-up sequences to maximize engagement while avoiding spam filters.

How To Scale A Cold Email Infrastructure (Cold Email Lead Gen Set Up Explained)

Setting Up Your Email Infrastructure

If you're looking to scale cold email campaigns effectively, having a solid email infrastructure is essential. Since February 2025, providers like Google and Yahoo have required proper email authentication to ensure deliverability.

Domain and Email Authentication Steps

Start by acquiring a domain specifically for cold outreach. For instance, if your primary domain is "business.com", you might use something like "business.co" or "business.io" for outreach purposes.

Once you have your domain, set up the following authentication protocols:

Authentication Protocol	Purpose	Implementation
SPF Records	Authorize sending IPs	Specify which servers are allowed to send emails on your behalf
DKIM	Verify email authenticity	Add a TXT record with the DKIM selector to your DNS
DMARC	Manage unauthorized emails	Define a policy (reject or quarantine) for unverified messages

"Email authentication gives mailbox providers confidence that the messages from senders are authentic and not sent by a bad actor. The more confidence a mailbox provider has that the messages you send are legitimate, the more likely that provider is to deliver the message to the inbox." - Will Boyd, SendGrid

Once your email authentication is configured, you can scale your outreach safely by spreading your sending activity across multiple mailboxes.

Multi-Mailbox Setup Guide

To avoid hitting email volume limits, distribute your sending activity across several mailboxes. Here’s how to do it effectively:

• Assess how many mailboxes you’ll need based on your daily email volume.
• Rotate between mailboxes to evenly spread the load.
• Stagger sending times to mimic natural email patterns.
• Regularly monitor delivery rates and adjust as needed.

This approach not only helps maintain deliverability but also reduces the risk of your emails being flagged as spam.

Using Mailforge for DNS Management

Mailforge simplifies DNS management, making it easier to handle multiple domains. Key features include:

• Automated setup for DNS records like SPF, DKIM, and DMARC.
• Bulk updates across multiple domains.
• SSL and domain masking for added security.

"We often hear 10x improvement as a target among startups. When it comes to cold email infrastructure setup, Mailforge provides 100x improvement! Procedures that usually took hours (setting DKIM, SPF, etc. records) for multiple domains, now take a few minutes."

Take Jimmy Durant, for example. He runs a lead-generation agency that brings in $25,000 per month. His team drastically reduced setup times, configuring 10 inboxes in just 10 minutes. This efficiency not only saved time but also cut hundreds of dollars in monthly infrastructure costs.

Safe Scaling Through Warm-Up

Once your email infrastructure is in place, the next step is to initiate a warm-up process. This step is crucial for building a strong sender reputation as you gradually scale your cold email campaigns.

30-Day Warm-Up Plan

Warming up email accounts requires a steady and gradual approach. Here's an example of a warm-up schedule to follow:

Week	Daily Sends per Account	Total Daily Volume*	Best Practices
Week 1	10–20	100–200	Start with highly relevant and engaged contacts
Week 2	20–30	200–300	Add initial follow-up sequences to your strategy
Week 3	30–40	300–400	Keep an eye on performance and fine-tune your messaging
Week 4	40	400	Wrap up the warm-up phase and prepare for full-scale campaigns

*Assumes 10 accounts are being warmed up simultaneously.

By systematically warming up your accounts, you’ll set the stage for consistent performance. The next step is keeping a close eye on how your emails are performing.

Tracking Email Performance

During the warm-up phase, monitoring key metrics is essential to identify and resolve issues quickly. Here are the critical metrics to track:

Metric	Target Benchmark	Action if Exceeded
Open Rate	60%+	Maintain your current approach
Bounce Rate	< 3–5%	Double-check and clean your email list
Spam Complaints	< 0.1%	Reevaluate your targeting strategy
Unsubscribe Rate	< 10%	Improve the quality of your content

If these metrics remain healthy, you can confidently adjust your sending strategy and distribute emails more evenly across your accounts.

Email Load Distribution

With your multi-mailbox setup and authenticated domains in place, balancing the email load is key to maintaining deliverability. Mailforge's automated DNS setup can help streamline managing multiple accounts and domains. Keep these tips in mind:

• Limit daily sends per account: Start with no more than 40 emails per account during the initial scaling phase.
• Rotate accounts: Switch between accounts to prevent overuse and maintain sender reputation.
• Monitor individual performance: Regularly check each account's metrics to ensure consistent deliverability.

Lastly, always prioritize sending to highly relevant leads. This not only helps maintain your account's reputation but also improves campaign outcomes.

Email Campaign Automation

Streamline your email outreach by using automation tools that manage large volumes of emails while still maintaining a personal and engaging touch.

Building Email Sequences

A well-structured email sequence can make all the difference in your campaign’s success. Here's a simple framework to follow:

Sequence Stage	Timing	Purpose	Key Elements
Initial Contact	Day 1	Introduce your value proposition	Highlight the problem and offer a clear solution
Follow-up 1	Day 3-4	Address common concerns	Include case studies and social proof
Follow-up 2	Day 7	Offer additional value	Share industry insights or useful resources
Final Outreach	Day 14	Create a sense of urgency	Add a time-sensitive offer and a strong call-to-action

Take this to the next level by incorporating personalization based on user data and behavior.

Mass Email Personalization

Personalization is no longer optional - it’s expected. According to research, 95% of marketers use some form of email personalization, but only 3% take advantage of live, real-time dynamic content. Meanwhile, 76% of buyers expect tailored experiences.

How to Collect and Use Data for Personalization

• Gather zero-party data directly from prospects (e.g., surveys or preference forms).
• Monitor engagement from previous campaigns to identify patterns.
• Segment your audience based on factors like purchase history, browsing habits, or stated preferences.
• Use dynamic content that adapts to each recipient’s behavior in real time.

"When personalization is done right, it's something subscribers are more likely to engage with. They're more likely to click on a product, browse your website, and make a purchase."

• Tracie Pang, Litmus Email Marketing Manager

With tools like Mailforge, you can go beyond basic personalization (like adding a first name). Advanced features include:

• Live content updates: Tailor email content dynamically based on user interactions.
• Behavioral triggers: Adjust email timing and messaging based on recipient actions.

Once your emails are personalized, the next challenge is managing responses efficiently.

Response Handling System

As your email campaigns scale, handling responses effectively becomes crucial. A well-designed response management system ensures no opportunity is missed. Here's how to structure it:

Component	Function	Automation Level
Initial Filtering	Weed out auto-replies and bounced emails	Fully automated
Sentiment Analysis	Identify and prioritize positive responses	AI-assisted
Response Categorization	Organize by interest level	Semi-automated
Follow-up Assignment	Direct inquiries to the right team member	Rule-based

To optimize response management:

• Use automation to summarize incoming emails for quick review.
• Leverage AI to draft responses, with human oversight for quality.
• Prioritize replies based on sentiment analysis to focus on high-value leads.
• Prepare templated responses for frequently asked questions or common scenarios.

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Maintaining Email Deliverability

It’s a harsh reality: 16.9% of marketing emails never make it to recipients' inboxes. This highlights just how crucial it is to stay on top of email deliverability practices.

Email List Management

A clean email list is the backbone of a strong sender reputation. For instance, OptinMonster achieved an impressively low bounce rate of 0.92% in Q1 2024, compared to the industry average of 10.29%. Regular upkeep of your email list can yield similar results. Here are some key actions to consider:

Action	Frequency	Impact
Remove Invalid Addresses	Weekly	Reduces hard bounces
Clean Inactive Subscribers	Monthly	Boosts engagement rates
Verify New Subscribers	Immediately	Blocks fake signups
Remove Role Accounts	Quarterly	Lowers spam complaints

Take Brian Dean’s experience as an example. He removed 28,018 inactive subscribers - about 35.5% of his list - and saw his open rate jump from 19.9% to 28.3%. This proves that trimming your list can have a direct and positive impact.

But a clean list alone isn’t enough. You also need to avoid spam filters by adopting smart strategies for email content and sending practices.

Spam Prevention Tips

Authentication protocols are your first line of defense, as discussed earlier in the section on Domain and Email Authentication. Beyond that, consider this: SendGrid found that creating an email preference center reduced unsubscribe rates by 20%. Keeping your emails out of spam folders also involves avoiding spammy words, limiting links, and steering clear of unnecessary attachments.

"If you send too many cold emails from a single email account, then your emails will go to spam." – George Wauchope, Founder of Emailchaser

Backup Systems

Once your list hygiene and spam prevention are in place, it’s time to safeguard your sending process with reliable backup systems. Here’s a breakdown of essential components:

System Component	Purpose	Implementation
Domain Rotation	Spread sending volume	Use multiple authenticated domains
IP Warming	Build sender reputation	Gradually increase daily sending limits
Monitoring Tools	Track deliverability	Tools like Google Postmaster Tools can help

Finally, remember that 21% of people unsubscribe because emails aren’t relevant. Combat this by using smart segmentation and targeting strategies. Keep an eye on key metrics like opens, clicks, and spam complaints. These insights help you identify and address problems before they damage your sender reputation.

Conclusion: Next Steps for Scaling

To scale cold email campaigns successfully, you need a strong foundation and constant oversight. With data showing that 20% of opt-in emails end up in spam folders, it's clear that proper setup and maintenance are non-negotiable.

Here’s a practical roadmap to help you scale confidently:

Scaling Phase	Key Actions	Expected Outcome
Infrastructure Setup	Configure DNS with DKIM, DMARC, and SPF	Achieve a 95% deliverability rate
Warm-up Period	Gradually increase sending volume	Build a strong sender reputation
Monitoring	Track deliverability metrics	Keep spam rate below 0.1%
List Management	Regularly clean and verify email lists	Maintain bounce rate under 3%

Each phase builds on the previous one, creating a system that supports growth while maintaining high deliverability. This approach ensures your emails reach inboxes, not spam folders.

Industry leaders have seen firsthand how the right tools and strategies can revolutionize cold email campaigns. For example:

"The simplicity and automation in the buying process of domains, DNS settings, inbox creation, forwarding, etc. Everything in one place. And when I had any doubts, the team through the chat or Slack solved it really quickly! I was hesitant because I’d only used Google Workspace, but my results have been great since using Mailforge!"

"We often hear 10x improvement as a target among startups. When it comes to cold email infrastructure setup, Mailforge provides 100x improvement! Procedures that usually took hours (setting DKIM, SPF, etc. records) for multiple domains now take a few minutes. Mailforge is also cost-efficient since you spend per mailbox ~3 times less than with Gmail. The support team replies in minutes and is happy to sort out issues proactively! Highly recommended for any organization where streamlined cold email infrastructure setup and scaling processes are needed."
– Karlo Binda, Founder of Leadsnack.co

Don’t forget: 71.6% of consumers delete emails immediately if they don’t display well on mobile devices. Use tools like an infrastructure calculator to determine how many domains and mailboxes you’ll need to meet your target volume.

FAQs

Why is warming up an email account important for sender reputation and deliverability?

Warming up an email account is a key step in building a positive sender reputation with email service providers. It’s all about gradually increasing the number of emails you send, showing that your account is being used responsibly and consistently.

This process helps lower the chances of your emails being marked as spam, which means better email deliverability rates. It ensures your messages land in your recipients' inboxes instead of getting lost in spam or junk folders. If you’re planning to scale a cold email campaign, taking the time to warm up your account is a must.

How can I keep my email list clean to improve deliverability?

Maintaining a clean email list is key to ensuring your campaigns land in the inboxes of active and interested subscribers. A good starting point is to regularly remove inactive contacts - those who haven’t opened an email in the last six months or after several unopened messages.

Before cutting them loose, though, try running a re-engagement campaign. This gives these subscribers a chance to confirm if they still want to hear from you. Another helpful strategy is segmenting your list to send tailored content to specific groups, which can reduce inactivity over time. By cleaning your list on a monthly basis - or at regular intervals - you’ll keep your audience engaged and safeguard your sender reputation.

How does personalizing email campaigns improve engagement and conversions?

Personalizing Email Campaigns: Why It Matters

Adding a personal touch to your email campaigns can work wonders for both engagement and conversions. Something as simple as including the recipient's name in the subject line can make your message feel more tailored, which often leads to higher open rates.

Taking it a step further, segmenting your email list based on factors like user behavior, preferences, or engagement levels allows you to send messages that truly resonate. When emails align with what your audience cares about, click-through rates improve, and conversions often follow suit.

By crafting emails that feel personal and relevant, you’re not just sending messages - you’re building a connection that inspires action.