When you transition to a custom sender domain, you are essentially introducing a “new face” to mailbox providers like Gmail, Outlook, and Yahoo. Because these providers don’t yet recognize your new domain, they may be suspicious of your initial emails.
Domain Warming is the process of gradually increasing your email volume to build a positive reputation. Follow this guide to ensure your emails land in the inbox, not the spam folder.
Best Practices Before You Begin
Before starting your warm-up, consider these two industry standards to ensure long-term success:
- Use a Subdomain: We strongly recommend using a subdomain (e.g., news.yourcompany.com.au) rather than your primary root domain. This “isolates” your marketing reputation. If your marketing emails ever face deliverability issues, your day-to-day business emails (like those sent via Outlook or Gmail) will remain unaffected.
- See our Custom Domains support article
Phase 1: The “Automation-First” Strategy
The safest and most effective way to begin warming a domain is to leverage your Automated Communications (Triggers).
Automations are the “secret weapon” of domain warming for two reasons:
- Low Daily Volume: Unlike a massive newsletter blast, automations send out small trickles of email throughout the day.
- High Engagement: Messages like Welcome Emails, Birthday Rewards, or Feedback Requests have much higher open and click rates than standard marketing sends.
Recommendation: Once your custom domain is verified, switch your highest-performing automated journeys to the new domain first. This creates a “heartbeat” of positive engagement signals that tells mailbox providers your domain is legitimate.
Phase 2: Targeted Segmentation (Using Filters)
When you are ready to start sending manual campaigns (blasts), do not send to your entire database at once. Instead, use specific filters to target your most “loyal” and “active” customers.
High engagement (opens and clicks) is the fastest way to build reputation. We recommend using these specific filters from our segmentation guide for your first few sends:
- Recent Visitors: Filter by customers who have visited in the last 30 or 60 days.
- Frequent Visitors: Target your “Top 10%” or those with a high total visit count.
- Highly Engaged: Send to those who have opened an email from you in the last 30 days.
Phase 3: The 14-Day Ramp-Up Schedule
Consistency is key. Mailbox providers look for predictable patterns. Follow this schedule for your manual campaign sends:
| Stage | Target Volume (Per Day) | Audience Focus |
| Day 1–2 | 500 – 1000 emails | Most engaged (opened in the last 30 days) |
| Day 3–4 | 2000 – 4000 emails | Most engaged |
| Day 5–6 | 8000 – 14,000 emails | Most engaged |
| Day 7–10 | 150,00 – 30,000 emails | Engaged (opened in the last 90 days) |
| Day 11–14 | 50,000 – 250,000 emails | Gradually include your full list |
Note: If you skip more than 2 days of sending, you may need to “pause” your volume increase or even step back one stage to maintain a consistent “heartbeat” for mailbox providers.
Phase 4: Monitoring Your Health
During the first 30 days of using a custom domain, you must monitor your metrics more closely than usual.
1. The 2% Bounce Rule
New domains should aim for less than 2% bounce. If your bounce rate is high, it indicates your data is stale and will adversely affect your reputation. Use an email verification service like ZeroBounce or Mailgun to clean your list before continuing.
2. Spam Complaints
Your spam complaint rate should be below 0.1% (1 complaint per 1,000 emails). If you see a spike in complaints, pause your warming immediately and review your content and targeting.
3. Proactive Engagement
If you find your warm-up emails are landing in the Junk folder, ask your team or a small group of loyal customers to:
- Move the email from “Junk” to “Inbox.”
- Mark the email as “Not Spam.”
- Save the sender as an email contact.
- This sends a powerful “reputation boost” to providers like Gmail.
Summary Checklist
- Verify Setup: Ensure SPF, DKIM, and DMARC are correctly configured.
- Clean Your Data: Run your list through a verification service.
- Start Automations: Switch on your Welcome and Birthday triggers first.
- Filter for Quality: Use TalkBox filters to find your most engaged 10% for the first week of manual sends.
- Watch the Stats: Keep bounces under 2% and complaints under 0.1%.
Need help setting up your segments or reviewing your warming stats? Contact the TalkBox Support Team.