Deliverability monitoring
Lists decay and DNS records break. RocketVerifier re-checks both on a daily or weekly schedule and alerts you the moment something slips, before it shows up as bounces.
100 free credits · No card required · Domain monitors use no credits
Two monitors
Bounces usually start with one of two problems: addresses that went bad, or a sending domain that lost its authentication. Monitor both.
Re-verify a saved list on a schedule and catch decay before your next campaign does.
Cost: 1 credit per email per run. Unknown results are refunded.
Watch a sending domain’s authentication and reputation so a DNS change never silently sends you to spam.
Cost: Free. Domain checks use DNS lookups only, no credits.
How it works
Add a sending domain or paste a list in the dashboard, or create one with POST /v1/monitors.
Run daily or weekly, set an alert threshold, and run it on demand whenever you like.
Every result is stored in the run history and compared with the previous run to spot regressions.
A regression fires a monitor.alert webhook with a severity and plain-English reasons. Route it to Slack, n8n or Zapier.
Alerts
Each alert carries a severity, the reasons in plain English and the previous and current results, signed like every RocketVerifier webhook.
{
"event_id": "b2d7e1f4-8a3c-4e59-9d61-0c7f2a5e4b18",
"event": "monitor.alert",
"timestamp": "2026-10-14T06:00:12+00:00",
"data": {
"monitor_id": "q8Fv2LmN0xR4tY7wZc1bAg",
"monitor_name": "Production sending domain",
"monitor_type": "domain_auth",
"severity": "warning",
"reasons": [
"DMARC record is no longer present",
"Authentication score dropped from 95 to 65"
],
"current": {
"domain": "mail.acme-corp.com",
"has_spf": true,
"has_dkim": true,
"has_dmarc": false,
"authentication_score": 65,
"is_blacklisted": false
},
"previous": {
"domain": "mail.acme-corp.com",
"has_spf": true,
"has_dkim": true,
"has_dmarc": true,
"authentication_score": 95,
"is_blacklisted": false
}
}
}FAQ
Email lists decay. People change jobs, companies shut down domains and mailboxes get disabled. A list that was clean three months ago can bounce more today. A list health monitor re-verifies it on a schedule and tells you when the share of bad addresses starts to climb.
It checks the domain’s SPF, DKIM and DMARC records and DMARC policy, calculates an authentication score, and looks up the domain’s mail servers on DNS blacklists. Major mailbox providers expect bulk senders to authenticate their mail, so a broken record can quietly push your mail to spam.
For a list, the share of invalid and risky addresses rising by at least your threshold since the previous run, or a first run that finds the list already in poor shape. For a domain, an SPF, DKIM or DMARC record disappearing, the authentication score dropping by at least your threshold, or a new blacklist listing, which is marked critical.
Daily or weekly, your choice per monitor. You can pause a monitor, change its schedule, or run it immediately at any time.
Domain authentication monitors are free. List health monitors use 1 credit per email per run, the same as any verification, and unknown results are refunded. If your balance cannot cover a run, it is skipped rather than partially charged.
Every alert is recorded in the monitor’s run history in the dashboard and sent to any webhook endpoint subscribed to monitor.alert. From there you can forward it to Slack, email or your incident tool with n8n, Zapier or your own code.
Add your sending domain for free and put your most important lists on a schedule.
100 free credits · No card required · Credits never expire