Why warmup matters
New domains and IPs don't have reputation yet. If you ramp too fast, mailbox providers may throttle, spam-folder, or block.
Warmup is a product feature
Treat warmup like any other reliability feature: planned, observable, and gradual.
A practical warmup plan
- Start with your most engaged recipients (internal + trusted users).
- Increase volume gradually (daily step function).
- Keep content consistent while warming.
- Watch bounce/complaint rates.
Pacing
Pacing spreads traffic over time so you don't trip provider throttles.
- If your account supports pacing controls, use them to avoid sudden bursts.
Measure success
Track:
- Delivery rate and latency
- Bounce rate
- Complaint rate
- Provider-specific throttling patterns
Next
- Deliverability foundations: Deliverability basics
- Simulate + validate event pipelines: Webhook simulator