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Domain Warmup

Gradually increase your daily email volume to build a positive reputation with ISPs and avoid spam folders.

What is Warmup?

When you start sending from a new domain or IP address, mail providers (like Gmail, Outlook, and Yahoo) are suspicious of high-volume traffic. To prove you are a legitimate sender, you must slowly "warm up" your domain by starting with a small number of emails and gradually increasing the limit over several weeks.

Sending 10,000 emails on day one from a new domain is the fastest way to get blacklisted.

Automated Warmup Flow

1

Configuration

Set your starting daily limit (default 25) and target limit (e.g., 5,000). Choose a ramp-up factor (default 1.5x daily).

2

Gradual Ramp-up

Every 24 hours of active sending, Transmit automatically increases your daily capacity until the target is reached.

3

Health Monitoring

The engine monitors bounce and complaint rates in real-time. If they exceed safe thresholds, warmup is automatically paused.

Health & Pausing

Transmit calculates a Health Score (0-100) based on your delivery metrics.

Warning State

Bounce rate > 3% or Complaint rate > 0.05%.

Critical State

Bounce rate > 5% or Complaint rate > 0.1% (Warmup Auto-Paused).