Domain reputation

What is domain reputation?

Domain reputation is the trust level that internet service providers (ISPs) and mailbox providers (Google, Microsoft, Yahoo) assign to a sending domain based on its historical sending behavior. It is the single most influential factor in whether emails from that domain land in the inbox or spam folder — more influential than message content, subject line, or send time.

Domain reputation is built on four signals: authentication completeness (is SPF, DKIM, DMARC configured?), bounce behavior (what percentage of sends are to invalid addresses?), spam complaint history (what percentage of recipients mark emails as spam?), and engagement patterns (do recipients open and reply, or ignore?). These signals are evaluated per domain — not per individual email.

For sales teams, domain reputation is a shared resource that every rep using the same domain is spending against. One rep running a high-bounce campaign damages the reputation for everyone sending from that domain. This is why dedicated outbound sending domains — separate from the primary business domain — are the standard practice for teams running cold outreach at any scale.

How domain reputation is measured

Google Postmaster Tools (free) shows reputation status for sends to Gmail addresses in four bands: High, Medium, Low, and Bad. Microsoft provides similar data through Smart Network Data Services (SNDS) for Outlook/Hotmail recipients. Validity's Sender Score (0–100) aggregates reputation data across multiple ISPs into a single numeric score.

The signals that move domain reputation:

• Spam complaint rate — the % of recipients who click 'This is spam.' Google's threshold: above 0.1% is a warning; above 0.3% triggers filtering. One percent-point move in spam complaints is enough to shift a domain from 'High' to 'Low' reputation within days.
• Hard bounce rate — the % of emails that permanently fail (invalid address). Keep below 2%. Above 5%, inbox providers begin treating the domain as a likely spammer sending to unverified lists.
• Engagement rate — the % of recipients who open, click, or reply. High engagement tells providers that recipients want email from this domain. Low engagement (no opens over many sends) trains filters to deprioritize this domain.
• Authentication status — are SPF, DKIM, and DMARC configured and passing? Unauthenticated sends from a domain reduce reputation score automatically.
• Sending consistency — sudden volume spikes (10x normal volume overnight) trigger anomaly detection regardless of other signals. Gradual, consistent growth is less suspicious than bursts.

Common domain reputation mistakes

1. Using the primary business domain for cold outreach. Damage to the primary domain affects all email from the company. Use secondary domains for cold sends.

2. Not monitoring reputation until inbox placement is already low. Check Google Postmaster Tools weekly, not after a campaign fails. Catching a reputation drop early (Low) is much easier to recover from than catching it late (Bad).

3. Sending to purchased lists without verification. Purchased lists have high invalid address rates, which drives bounces, which damages reputation. Verify all addresses before the first send.

4. Ignoring opt-out requests. Recipients who ask to be removed but keep receiving email will escalate to spam complaints. Honor unsubscribe requests within 24 hours. As of 2024, Google requires one-click unsubscribe for senders above 5,000 messages/day.

5. Volume spikes from new sequences. Launching a 500-contact sequence overnight from a domain averaging 30 sends/day signals anomalous behavior. Ramp new sequences over days, not hours.

How Gangly's outreach model protects domain reputation

Gangly's Outreach Writer generates individual, rep-reviewed messages sent one at a time from the rep's own inbox. The send behavior — consistent daily volume, genuine replies from engaged prospects, natural cadence spacing from the Workflow Sequencer — builds positive reputation signals rather than the anomalous patterns that trigger reputation damage.

Because Gangly is not a bulk sender (every message goes through rep review before sending), the natural volume ceiling is much lower than a mass email tool. A rep sending 30–40 reviewed, signal-triggered messages per day is generating exactly the kind of consistent, engaged sending behavior that builds domain reputation over time.

See how Outreach Writer works →

Frequently asked questions