🏷️ Custom domains are available on all Marsello pricing plans.
Start warm-up by emailing your most engaged customers. This boosts open rates, protects deliverability, and helps your new sending domain build a strong reputation.
Fluctuations in email deliverability can occur with newly authenticated domains as inbox providers build trust in your domain or 'from' address. Starting with smaller, engaged segments allows you to establish a positive sender reputation.
Why Is domain warm-up important, and who are the best customers to start with?
Use Marsello’s built-in filters to create a warm-up segment of your most engaged customers.
⚠️ Important: To ensure your warm-up segment performs effectively, avoid the following:
Creating a segment of your entire subscriber base
Reactivating old or inactive customers (typically those inactive for 180–365+ days)
Importing large lists and emailing them immediately
Running multiple high-volume campaigns on the same day
These actions can harm your deliverability and slow down the warm-up process.
To create a custom warm-up segment in your Marsello app admin:
1.Go to Customers > Segments
2. Click Create Segment
3. Name your custom segment
4. Click Add Condition or Add Group
5. Select the field that you want to segment your customers by
6. Next to the field, select the operator that you'd like to use.
📝 Note: There are different operators depending on which field name you select:
True or false based field names have: Is and Is not
Date-based field names have: Is, Is not, before, after, between, X days ago.
Number-based field names have: Is, Is not, greater than, less than, and between.
7. Then, select or enter the value
8. Click Add Condition to add another segment condition
Repeat the above steps to add more conditions. You can add as many conditions to your segment as needed.
💡 Pro Tip: Create an effective warm-up segment by targeting customers who meet any of the following criteria:
Opened an email in the last 90 days
Clicked an email in the last 90 days
Made a purchase in the last 90 days
Focusing on this highly engaged group boosts open rates, improves engagement, and helps your new domain build a strong sender reputation faster.
What volume schedule should I use for a safe domain warm-up?
To build sender reputation gradually and maintain strong deliverability, follow Marsello’s recommended warm-up progression:
To gradually build a strong sender reputation and protect deliverability, increase your email volume in controlled stages. Using percentages helps you scale appropriately regardless of your total list size.
Days 1–3
Send to 1–2% of your most engaged customer segment
Focus on those active in the last 30–60 days
Days 4–7
Send to 3–5% of your
Focusing in on those active in the last 90 days
Week 2
Send to 5–10% of your list per send, depending on engagement
Include slightly older but still warm contacts (active in the last 120 days)
Week 3+
Gradually increase to 15–25% per campaign
Introduce broader segments slowly, in layers
Continue monitoring engagement before expanding further
This percentage-based approach creates safer, more consistent warming for lists of any size and helps ensure strong inbox placement as your domain reputation grows.
Which Marsello tools should I use to warm up my domain?
Marsello offers several tools that can help you warm up your new sending domain safely and effectively. The key is to keep early volume low and engagement high including:
campaigns
automations
Send Small, High-Quality Campaigns
Start with short, simple campaigns sent to your engaged segment, such as:
“Welcome back!” messages
Helpful content or tips
Loyalty reminders or exclusive offers
New arrivals or store updates
To maximize engagement during warm-up, make sure your emails are:
Light on images
Personalized when possible
Focused on a single, clear CTA
Use Automations (Carefully)
Certain low-volume automations can continue running during warm-up, including:
Loyalty-based workflows
Birthday emails
Post-purchase follow-ups
These automations naturally target engaged customers, which helps maintain a healthy reputation.
Avoid enabling high-volume flows (such as win-back or reactivation automations) until your domain is fully warmed up, as they can send to colder audiences and risk deliverability issues.
Which metrics should I track in Marsello while warming up my domain?
Use Campaign Reports + Deliverability Insights to watch for:
Open rate above 20% = great
Bounce rate under 2% = healthy
Spam complaints under 0.1% = safe
Gmail/Outlook blocking = pause warm-up
If your engagement drops → stop scaling for 2–4 days before sending more.