When you launch a new domain for sending marketing emails, you’re starting with a blank slate — and Internet Service Providers (ISPs) don’t yet know if you’re a trustworthy sender or a potential spammer. This is why a domain warm-up process is critical.
Warming up your domain builds a positive sender reputation with ISPs, ensures your emails reach primary folders rather than spam folders, and lays the foundation for high engagement and conversions over time.
Below, we’ll cover how to warm up your sender domain step-by-step, the best types of emails to send during this process, and proven strategies to maximize deliverability.
Why Warming Up a Domain Matters
ISPs like Gmail, Outlook, and Yahoo use sophisticated filters to protect users from spam. If your brand suddenly sends tens of thousands of emails from a new domain, the filters will in all likelihood flag you as suspicious — especially if recipients don’t engage.
A proper warm-up:
- Builds trust with ISPs
- Improves inbox placement and open rates
- Avoids blacklisting and sending restrictions
- Strengthens domain and IP reputation for the long term
Ramping
Ramping is a process that aids in the overall warming process to become a reputable sender, whether you are using a dedicated or shared IP. Ramping involves starting out with smaller volumes of email sends, and then gradually increasing that volume over time.
Step-by-Step Process to Warm Up a New Sender Domain
1. Prepare Your Domain for Sending
Before sending a single email:
- Set up SPF, DKIM, and DMARC records for authentication
- Ensure your domain name is professional, relevant, and not previously blacklisted
- Verify your domain in your email service provider and Google Postmaster Tools
- Create a subdomain for sending (e.g., mail.yourbrand.com) to separate marketing activity from your root domain
2. Start with a Small, Highly Engaged Audience
Begin by emailing only your most engaged subscribers — people who have recently interacted with your brand and are likely to open and click. This helps ISPs see positive engagement signals.
Example:
- Day 1 – Send to 50–100 of your most active subscribers
- Day 2–5 – Gradually increase to 200–500 daily
- Weeks 2–4 – Continue scaling, aiming to double or add 20–30% more each day
- By Week 4–6 – You can typically send to your full list if engagement remains strong
3. Send the Right Type of Emails During Warm-Up
Your first emails should feel personal, valuable, and highly relevant to encourage opens and clicks. Avoid heavy promotions at first.
Best warm-up email types:
- Welcome Emails – Thank subscribers for joining, remind them what to expect
- Exclusive Content – Send tips, guides, or behind-the-scenes stories
- Survey or Feedback Requests – Encourage responses to drive interaction
- Special Thank You Offers – Reward your most loyal subscribers with discounts
- Brand Story Emails – Share your mission and values to build connection
4. Maintain Consistency
ISPs favor senders with predictable behavior.
- Send at consistent times each day or week
- Avoid large spikes in volume — sudden jumps can trigger spam filters
- Keep your sending pattern steady, even after warm-up
5. Monitor Engagement & Adjust
During warm-up, track:
- Open rates – Should be high in early days (over 40–50% for engaged lists)
- Click-through rates – Positive clicks show ISPs your content is wanted
- Spam complaints – Keep below 0.1% (Gmail flags senders above 0.3%)
- Bounce rates – Keep hard bounces below 2%
If engagement drops or spam complaints rise, slow down your sending until metrics recover.
6. Avoid Spam Triggers
To prevent deliverability issues:
- Avoid excessive use of promotional keywords in subject lines (e.g., “FREE,” “100% OFF”)
- Keep your HTML clean and lightweight
- Don’t send cold emails from your warm-up domain
- Always include a clear unsubscribe link
Proven Strategies to Build Trust with ISPs
- Prioritize engagement over volume – A smaller list that engages is better than a massive unresponsive one
- Use segmentation – Send different emails to different audience segments for higher relevance
- Authenticate everything – SPF, DKIM, and DMARC setup is non-negotiable
- Clean your list regularly – Remove inactive or bouncing addresses
Conclusion
Warming up your sender domain is a strategic, deliberate process that builds the foundation for long-term email marketing success. By starting small, sending high-value emails, and gradually scaling, you earn the trust of ISPs, avoid spam filters, and ensure your messages consistently land in the inbox.
Done right, this process transforms your new domain from a blank slate into a trusted, high-reputation sender identity — which is the key to maximizing email ROI.
