Understanding Deliverability Metrics
Learn about bounce rates, complaint rates, and ISP breakdowns
Understanding Deliverability Metrics
Deliverability is the measure of how successfully your emails reach subscribers' inboxes. Mailnaptic provides a detailed Deliverability Dashboard that tracks bounce rates, complaint rates, and ISP-level breakdowns so you can identify and resolve delivery problems quickly.
Accessing the deliverability dashboard
- Navigate to Organization Settings from the sidebar.
- Scroll to the Deliverability section, or click Deliverability in the sticky navigation bar.
- The dashboard shows your current deliverability health for each verified sending domain.
Key metrics explained
Bounce rate
Your bounce rate is the percentage of sent emails that were rejected by the receiving mail server. Mailnaptic tracks two types of bounces:
- Hard bounces — Permanent delivery failures, usually because the email address does not exist. Mailnaptic automatically suppresses contacts that hard bounce to protect your sender reputation.
- Soft bounces — Temporary failures such as a full mailbox or a server that is temporarily unavailable. These are retried automatically.
A healthy bounce rate is below 2%. If your bounce rate exceeds 5%, you should review your list hygiene practices.
Complaint rate
The complaint rate measures how often recipients mark your email as spam. This is the single most important metric for deliverability. Major mailbox providers like Gmail and Yahoo use complaint rates as a primary signal for filtering decisions.
- Warning threshold — 0.1% complaint rate. Mailnaptic logs a warning when this threshold is crossed.
- Critical threshold — 0.5% complaint rate. At this level, your sending reputation is at serious risk and deliverability will degrade.
Mailnaptic monitors complaint rates continuously and alerts you when thresholds are breached. These thresholds are configurable at the platform level.
ISP breakdown
The deliverability dashboard includes an ISP Stats section that shows your top 10 ISP domains ranked by complaint and bounce counts. This breakdown helps you identify whether delivery problems are concentrated at specific mailbox providers. For example, if your Gmail bounce rate is normal but your Yahoo complaint rate is elevated, you can investigate Yahoo-specific issues such as authentication failures or content filtering.
Domain health indicators
Each domain in your organization displays a color-coded health badge:
- Green — All DNS records (SPF, DKIM, DMARC) are properly configured and verified.
- Yellow — Some records are missing or misconfigured.
- Red — Critical authentication records are missing, which will severely impact deliverability.
DMARC status
The dashboard shows your DMARC policy in human-readable labels. DMARC tells receiving servers what to do when an email fails SPF or DKIM checks:
- None — Monitor only, no enforcement. Good for initial setup.
- Quarantine — Failed emails are sent to the spam folder.
- Reject — Failed emails are blocked entirely. This is the strictest and most protective policy.
Improving your deliverability
- Authenticate your domain with SPF, DKIM, and DMARC records.
- Clean your list regularly by removing unengaged contacts.
- Use double opt-in to ensure valid, consenting subscribers.
- Monitor your complaint rate closely and investigate spikes immediately.
- Warm up new domains gradually before sending at full volume.
- Include a clear and easy unsubscribe link in every email.
Consistent monitoring of these metrics is essential for maintaining a strong sender reputation and ensuring your emails reach the inbox.