Cold Email Infrastructure (CEI) is how CallSine sends large-scale outbound email without hurting your sender reputation. It runs entirely in the background—so you can focus on content and targeting while the system handles deliverability.

If you want to set up CEI or add more inboxes, contact your CallSine sales representative.

1. Dedicated Domains & Inboxes

CallSine uses secondary domains that closely match your main business domain. Each domain has dedicated inboxes used only for cold outreach—keeping your primary domain safe.

2. Domain Warming

Before any inbox sends outreach, CallSine warms it by sending and receiving messages in realistic patterns. This builds trust with email providers and reduces the risk of landing in spam.

3. Smart Email Distribution

Outreach is spread evenly across all active inboxes. This prevents overuse, maintains high deliverability, and ensures consistent sending patterns.

4. Deliverability Safeguards

The system automatically enforces best practices, including daily send limits (up to 50 emails per inbox) and bounce/spam rate monitoring.

CallSine automatically balances outreach across inboxes. This helps maintain deliverability and ensures no inbox is overused.

Important: Each cold email inbox can safely send up to 50 emails per day.

Note: The most effective way to increase your outbound volume is by increasing your number of cold email inboxes. Reach out to your sales rep to explore options.

Note: The easiest way to increase your daily sending volume is to add more cold email inboxes. Contact sales to get started with Cold Email Infrastructure or to expand your current inboxes and domains.