Email warmup for high-volume cold outreach

Warming up your email address, domain, and IP is essential to ensure deliverability and build a good sender reputation when planning a high-volume cold outreach campaign. Here’s a practical approach to warmup for high-volume cold outreach:

1. Start small and gradually increase the volume

• Begin with a low volume, such as 50-100 emails per day, and increase by 10-20% every few days. This gradual approach allows email service providers (ESPs) to track consistent, non-spammy behavior, which is crucial for establishing trust in high-volume scenarios​.

2. Prioritize engagement

• For the initial warmup phase, send emails to recipients more likely to engage, such as existing connections or internal addresses. High open and click-through rates signal ESPs that your emails are relevant, supporting better inbox placement. This engagement is especially valuable when warming up for cold outreach, where recipients are less familiar with your brand​

3. Authenticate with SPF, DKIM, and DMARC

• Proper authentication is a must-have for building a credible sender reputation. Setting up SPF, DKIM, and DMARC records authenticates your domain, ensuring ESPs can verify that your emails are legitimate. Without these records, your emails are more likely to be filtered out by ESPs, especially Google and Microsoft​.

4. Monitor key metrics

• Track bounce rates, click-through rates, and spam complaints. High bounces or complaints can indicate deliverability issues, so it’s best to adjust your strategy before scaling up. Tools like Google Postmaster and monitoring services such as WUI provide insights into domain health and engagement, helping you maintain a solid warmup path​.

5. Consider automating warmup

• For large-scale cold outreach, automated warmup tools like Warmup Inbox streamline the warmup process by managing incremental volume increases and engagement tracking. This automation ensures consistent delivery without manual intervention and is especially useful for maintaining high deliverability rates at scale.

6. Maintain cold outreach in parallele of your cold outreach

• Design you cold outreach so that you are sending 1 cold outreach email for 2 to 4 warmup email.

7. Distribute workload accross multiple inbox

It is better to send 20 email per days from 2 inboxes than 40 emails per day from on single inbox.