Outbound email is one of the most efficient ways for founders and B2B teams to generate pipeline. Yet too often, new domains get burned before they ever gain traction.

Founders facing the same challenge with visibility can also learn how to do SEO on a small budget and still rank — a parallel low-cost channel that rewards consistency over shortcuts.

A brand-new domain has no history with inbox providers. If you start blasting cold emails right away, you don’t just risk low open rates. You risk long-term deliverability damage that can take months to undo.

This guide breaks down how to properly warm up a new domain so your emails actually land in inboxes. It covers why warm-up matters, the technical setup you can’t skip, a detailed step-by-step playbook, common mistakes to avoid, and advanced strategies used by experienced teams.

‍

What is domain warm-up and why it matters

Domain warm-up is the deliberate process of building a positive sending reputation with email providers before scaling outbound campaigns.

Inbox providers like Gmail and Outlook decide inbox placement based on trust. They track signals such as:

• How many emails are being sent from a domain
  
  
• How recipients engage with those emails (open, reply, mark as spam)
  
  
• Whether the sending infrastructure looks legitimate
  
  
• Whether patterns look like natural business communication or automated spam
  
  

Without history, a new domain looks suspicious. Sending 500 cold emails on day one is the equivalent of a stranger shouting through a megaphone in a crowded room. Nobody listens, and security quickly steps in.

What’s at stake if you skip warm-up?

• High bounce rates
  
  
• Immediate spam folder placement
  
  
• Domain blocks by major providers
  
  
• Loss of time, money, and opportunities
  
  

For startups relying on outbound sales, this isn’t a minor inconvenience. It can stall growth entirely. Warm-up is the insurance policy against that outcome, and a crucial part of any early-stage growth strategy.

‍

The framework for domain warm-up

Every successful warm-up process balances three elements. Miss one, and deliverability suffers.

1. Technical foundation

Inbox providers look for signals of authenticity. SPF, DKIM, and DMARC aren’t optional—they’re the bare minimum. Proper setup proves your domain is who it claims to be and prevents spoofing.

Beyond authentication, align these technical details:

• Reverse DNS (rDNS): Ensure your sending server IP resolves back to your domain.
  
  
• Custom tracking domains: If using a sending platform, set up branded tracking domains rather than default shared ones.
  
  
• Consistent sending IPs: Switching IPs too often disrupts reputation building.
  
  

2. Controlled sending patterns

Email reputation grows like credit history. Gradual, consistent patterns are rewarded. Spikes and irregularities raise suspicion.

During warm-up, start small and increase sending slowly. Spread emails evenly across hours and days to mimic human behavior.

3. Engagement signals

Inbox providers weigh recipient behavior heavily. Positive engagement (opens, clicks, replies) boosts reputation. Negative engagement (spam complaints, bounces, unsubscribes) hurts it.

This means your first emails should be to trusted contacts who will open and respond. Think of it as “teaching” inbox providers that people like receiving your emails.

‍

Step-by-step guide to warming up a new domain

Step 1: Configure authentication and infrastructure

Before touching a send button, lock in your technical base.

• Publish an SPF record that authorizes your sending service.
  
  
• Add a DKIM record to cryptographically sign each email.
  
  
• Set up DMARC to specify alignment and receive reports.
  
  
• Configure BIMI (optional, but adds brand trust with logo display).
  
  
• Double-check DNS propagation using tools like MXToolbox.
  
  

Pro Tip: Don’t skip DMARC. Even if you set it to “none” initially, having a record improves trust and gives visibility into misuse.

Step 2: Create authentic mailboxes

Set up more than one mailbox under the new domain. A healthy domain looks like a real company, not a single “sales@” account.

• Examples: alex@, team@, info@
  
  
• Add signatures, profile photos, and contact details
  
  
• Send a few internal test emails to check formatting and headers
  
  

Step 3: Start with low, human emails

The first 5–10 emails per mailbox should go to friends, colleagues, or even your personal accounts. These recipients should reply naturally, creating back-and-forth engagement.

Avoid cold prospects at this stage. Treat it as a controlled sandbox.

Step 4: Gradual ramp-up

Here’s a safe benchmark schedule (per mailbox):

• Week 1: 5–10 emails per day
  
  
• Week 2: 20–30 emails per day
  
  
• Week 3: 40–60 emails per day
  
  
• Week 4: 80–100 emails per day
  
  

This pace can vary depending on provider response. If deliverability dips, hold volume steady before increasing again.

Step 5: Focus on engagement

During warm-up, ask contacts to reply. Short responses like “Thanks” or “Got it” are enough. The goal is to drive positive engagement signals.

Mix in inbound activity too. Subscribe to newsletters, sign up for SaaS tools, and interact with confirmation emails. This builds natural-looking inbound-outbound balance.

Step 6: Monitor and adjust

Use reputation monitoring tools to track progress:

• Google Postmaster Tools for Gmail-specific insights
  
  
• Microsoft SNDS for Outlook deliverability
  
  
• Third-party tools like Warmup Inbox, GlockApps, or MailGenius
  
  

If reputation drops, slow volume growth. Identify patterns—are bounces too high? Are emails landing in promotions or spam?

Step 7: Layer in outbound carefully

Once a domain consistently handles 50–100 daily emails with strong engagement, begin sending real cold outreach. Start small and keep personalization high.

Structure outbound like this:

• Send batches of 10–20 cold emails per day
  
  
• Interleave them with warm-up and friendly traffic
  
  
• Monitor replies and spam flags closely
  
  

Over time, the ratio can shift toward outbound. But warm-up emails should always remain part of the mix.

‍

Advanced warm-up strategies

For teams aiming to scale quickly or manage multiple outbound reps, these advanced tactics provide leverage.

Use multiple domains

Instead of relying on a single outbound domain, purchase 2–4 related domains. Example:

• maincompany.com (core domain, never used for cold outbound)
  
  
• getmaincompany.com
  
  
• try-maincompany.com
  
  
• maincompany.co
  
  

Warm each up separately. This distributes risk and allows higher total volume without burning the main domain.

Automate warm-up sequences

Specialized tools can automate warm-up by sending small volumes of emails between a network of addresses and marking them as opened and replied. While not a replacement for authentic engagement, these tools can accelerate reputation building.

Stagger sending times

Sending 200 emails at exactly 9:00 AM looks automated. Stagger sends randomly across hours. Most outbound platforms allow scheduling with time windows.

Blend cold with transactional

If your business has legitimate transactional emails (invoices, confirmations), sending them from the new domain helps diversify traffic. Just ensure they’re properly formatted and expected by recipients.

‍

Common mistakes to avoid

Mistake 1: Scaling too aggressively

Jumping volume too quickly overwhelms reputation. Even if you don’t get blocked immediately, inbox providers silently filter emails to spam.

Fix: Increase in small increments and monitor before scaling further.

Mistake 2: Sending cold campaigns too early

Prospects don’t know you and are less likely to engage. During early warm-up, this creates negative signals.

Fix: Start only with trusted contacts until your domain proves stable.

Mistake 3: Neglecting list hygiene

Unverified lists cause bounces, which destroy reputation.

Fix: Run every prospect list through an email validation service before uploading. [INTERNAL LINK: How to Validate an Email List]

Mistake 4: Using the main brand domain

Burning your primary company domain (yourcompany.com) harms every department, not just sales. Once spam filters distrust it, even internal emails can suffer.

Fix: Always use secondary domains for outbound.

Mistake 5: Ignoring spam complaint rates

One “Report Spam” click carries more weight than 10 opens. High complaint rates are a fast track to blacklisting.

Fix: Keep copy relevant, targeted, and respectful. Always include a clear opt-out.

‍

Checklist: Warming up a new domain

• Configure SPF, DKIM, DMARC
  
  
• Create multiple real mailboxes
  
  
• Start with 5–10 daily emails to known contacts
  
  
• Gradually increase volume weekly
  
  
• Encourage replies and engagement
  
  
• Monitor reputation and adjust pace
  
  
• Introduce cold outreach only after 3–4 weeks
  
  
• Keep outbound on separate domains from primary brand
  
  

‍

Conclusion and next steps

Domain warm-up is less about technical tricks and more about building a reputation of trust. Inbox providers reward patience, authenticity, and consistency.

Key takeaways:

• Authentication (SPF, DKIM, DMARC) is the foundation.
  
  
• Warm-up requires gradual volume increases.
  
  
• Engagement is more important than raw send numbers.
  
  
• Monitoring deliverability prevents small issues from becoming fatal.
  
  
• Never risk the primary brand domain on cold outreach.
  
  

When done right, a warmed-up domain becomes a predictable, scalable asset for outbound growth. When rushed or ignored, it becomes a liability.

For founders and teams serious about outbound, get our free Outbound Email Warm-Up Checklist by subscribing to the newsletter. It includes daily pacing templates, tool recommendations, and troubleshooting tips.

‍