Domain health

Domain health is the overall sending reputation of your outreach domains. A healthy domain consistently reaches the inbox. A damaged domain can take weeks to recover — and in severe cases, may not recover at all.

Key health metrics

Bounce rate

The percentage of emails that couldn't be delivered. Keep this below 2%. Hard bounces (permanent failures — invalid addresses or non-existent domains) are the most damaging. Soft bounces (temporary failures — full inbox, server timeout) are less critical.

Spam complaint rate

The percentage of recipients who mark your email as spam. Keep this below 0.1%. Even a small number of spam complaints can trigger ISP-level filtering against your domain.

Open and reply rates

Positive engagement signals matter. ISPs interpret opens and replies as evidence that recipients want your emails. Low open rates (below 20%) can indicate spam folder placement, not just weak subject lines.

Sending consistency

Sudden volume spikes — especially from new or recently warmed domains — raise flags. Keep sending patterns consistent and ramp up gradually when increasing volume.

Authentication status

SPF, DKIM, and DMARC must pass on every send. Authentication failures directly impact deliverability and domain trust scores.

How to monitor domain health

• Campaign analytics — Track open rate, bounce rate, and reply rate per campaign

• MXToolbox — Verify DNS records and check if your domain is on any blocklists

• Mail Tester — Score an email before launching to identify content and authentication issues

• Google Postmaster Tools — If sending to a significant number of Gmail addresses, register your domain for detailed reputation data

If domain health degrades

1. Pause campaigns on the affected domain immediately.

2. Reduce sending volume significantly.

3. Identify the root cause — high bounces, spam complaints, or authentication failures.

4. Contact your GTM strategist. Recovery plans depend on the severity and cause.