Inbox warming is a crucial step for anyone looking to maximize email deliverability and build a trustworthy sender reputation. Whether you're launching a new email domain, switching email service providers, or scaling up your outbound campaigns, properly warming up your inbox ensures your messages consistently land in recipients' primary inboxes—not the dreaded spam folder.
Failing to warm up an inbox can lead to high bounce rates, increased spam complaints, and even blacklisting by email providers. To help you avoid these pitfalls, we’ve outlined the top best practices for inbox warming. By following these strategies, you can establish credibility, maintain high engagement rates, and ensure your emails reach their intended audience
Best Practices for a Strong Sender Reputation
Gradually Increase Email Volume
* Highly Recommended
Start with a low volume of emails (10–20 per day) and incrementally increase over a few weeks. This slow ramp-up builds a positive sender reputation and reduces the risk of triggering spam filters. You can update your daily send limit in your email settings to manage this process easily. You can learn more here: Email Settings
Use a Reputable Warm-Up Service
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Consider leveraging automated inbox warming services to optimize deliverability and minimize manual effort. These services engage in authentic conversations with trusted inboxes to establish credibility.
Send to Engaged and Valid Recipients Only
Ensure you are emailing verified, active users who have opted in or shown engagement. Sending emails to unverified or inactive addresses increases bounce rates and damages sender reputation.
Try using email Total AI score or email validation to find valid emails. Learn more about Total AI and Email Validation
Prioritize High-Quality Content
Craft emails that are relevant, engaging, and personalized. Avoid spammy language, excessive links, and overuse of promotional phrases to maintain a high deliverability rate.
Try using Templates with Dynamic Variables
Warm Up Each Sending Domain Separately
If using multiple sending domains, warm them up individually to prevent potential reputational damage from one affecting others. Treat each domain’s warm-up process independently. You can manage and update each domain’s daily send limit in your email settings to align with your warm-up strategy. You can learn more here: Email Settings
Authenticate Your Emails with SPF, DKIM, and DMARC
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Proper email authentication signals trustworthiness to email providers. Set up SPF, DKIM, and DMARC records correctly to ensure inbox placement and security.
Limit the Number of Emails Per Recipient
Avoid bombarding recipients with multiple emails per day. Sending excessive emails to the same address can lead to spam complaints and lower engagement rates.
Tip: Reference the contacts "Engagement status" filtering on this in My Contacts, Activity, or a list can help you see who you've emailed and who you haven't. This status is also in the Contact Profile (flyout)
Maintain a Consistent Sending Schedule
Consistency in sending patterns helps build sender reputation. Sudden spikes or irregular sending behavior can trigger spam filters and negatively impact deliverability. To maintain consistent timing, you can set a business hours schedule in your email settings to ensure emails are only sent during designated windows.
Learn more about “Business Hours," check out Email Settings
Monitor Key Deliverability Metrics Regularly
Track open rates, bounce rates, spam complaints, and inbox placement to identify and address potential issues early. Regular monitoring ensures adjustments can be made promptly to maintain inbox placement.
Interested in learning more about monitoring engagement activity in Seamless.AI? Check out Using the Activity Page to Track Emails & Calls
Avoid Attachments and Excessive Links in Initial Email
Attachments and multiple links in warm-up emails can trigger spam filters. Stick to plain-text or lightly formatted emails until a strong sender reputation is established.