Blacklist Monitoring — Know You're Listed in Under 60 Seconds, Before Your Emails Stop Arriving

Your ESP manages the reputation of their shared IPs — but that's only half the picture. Your sending domain can be blacklisted completely independently of which IP sends your email. Spamhaus DBL, URIBL, and SURBL list domains, not IPs — so switching ESP or upgrading your plan doesn't fix it. If you're on a dedicated IP (which most serious senders eventually move to), you own that IP's reputation entirely.

ValidPeak monitors both your domain and your IP, so you're covered regardless of how your ESP handles the infrastructure side.

Blacklist problems have a very specific fingerprint: a sudden, steep drop — open rates that go from 35% to 6% overnight, or a campaign that just stops generating replies. Engagement issues are gradual and affect certain segments. Algorithm issues tend to be ISP-specific. A blacklist listing is usually universal and immediate.

The fastest way to know for sure is to run a free check at ValidPeak's blacklist checker — it queries 200+ databases in real time and tells you in under 30 seconds whether you're listed and on which specific blacklist.

They're different things and both matter. An IP blacklist (like Spamhaus SBL or Barracuda) blocks emails based on the server that sent them. A domain blacklist (like Spamhaus DBL) blocks based on the domain in your From address or email links. You can be listed on one without the other.

If you're on Spamhaus SBL but not DBL, switching to a different sending IP might temporarily help — but you'd still have a problem you haven't fixed. ValidPeak monitors both separately and gives you a Blacklist Health Score that reflects your combined reputation, so you see the full picture in one place.

MXToolbox charges $129/month for blacklist monitoring as a standalone product. ValidPeak Pro is €142/month and includes blacklist monitoring plus DMARC monitoring, domain warmup tracking, and Campaign Intelligence — which scores your sending risk before every campaign.

MXToolbox is primarily a manual-check tool; ValidPeak runs continuous automated monitoring 24/7 and alerts you in under 60 seconds of a new listing. If you only need occasional blacklist checks, MXToolbox's free tier works. If you need to know the moment something changes — before it affects a scheduled send — that's where ValidPeak's real-time monitoring is the meaningful difference.

It's a permanent free plan — no trial period, no credit card, no expiry. On the free plan you get one domain or IP monitored across 200+ blacklists with weekly automated checks, email alerts on new listings, a Blacklist Health Score, and step-by-step delisting guidance.

The limitation compared to paid plans is frequency: weekly checks vs. every 4 hours on Starter or continuous real-time on Pro. For a small business with one domain that isn't sending campaigns daily, the free plan covers the core use case. Where paid plans matter is if you need to catch a listing within minutes — not the next weekly scan.

Yes. The alert doesn't just say "you're listed" — it tells you which specific blacklist flagged you, the IP or domain that's listed, the likely reason based on the blacklist's criteria, and a direct link to that blacklist's delisting form with instructions on what to include in your request.

The one thing ValidPeak is explicit about: don't submit a delisting request before fixing the root cause. Submitting without fixing means you'll be re-listed within days, and repeated requests make future removals harder. ValidPeak's delisting guidance walks you through fixing first, then requesting removal in the right sequence.

Monitoring is part of it — catching a re-listing in under 60 seconds instead of days. But the more useful protection is fixing what caused it in the first place.

ValidPeak's Campaign Intelligence scores your domain health before every send based on five signals, one of which is your Blacklist Health Score. If your score drops below 70, Campaign Intelligence flags your next campaign as at-risk before you send it. That way you're not finding out about a re-listing after a campaign underperforms — you find out before you schedule it.

No — each blacklist has its own criteria and operates independently. Spamhaus SBL lists IPs that sent spam to their traps. Spamhaus XBL lists compromised servers. Spamhaus DBL lists domains. SpamCop is user-reported and auto-expires in 24 hours. Barracuda focuses on volume and complaint patterns.

You can be on Spamhaus SBL without being on Barracuda or SURBL. ValidPeak monitors all of them separately and shows you exactly which ones have flagged you — because the delisting process for each is different, and treating them as the same problem leads to wasted effort.

Multiple domains and Slack alerts are both available on the Starter plan (€28/month, billed annually), which covers up to 5 domains or IPs with alerts in under 4 hours via email and Slack. The Pro plan is unlimited domains with continuous real-time monitoring and alerts in under 60 seconds, across Email, Slack, Jira, and Microsoft Teams.

All in one dashboard — you don't need a separate monitoring tool, a separate Slack integration, or a separate multi-domain management layer.

Blacklist monitoring takes about two minutes to set up. Create a free account, add your domain or IP, and ValidPeak starts monitoring immediately. No DNS changes required — unlike DMARC monitoring, which needs a DNS record update, blacklist monitoring just needs to know what to watch.

You'll have your first Blacklist Health Score within a few minutes of adding your domain, and ValidPeak will immediately tell you if you're already listed anywhere across the 200+ databases it tracks.