45+ blacklists, one score, zero surprises.
One listing on the wrong DNSBL can silently halve your deliverability. SenderSignal checks every asset against 45+ blacklist and reputation sources and turns the result into a single 0-100 score your whole team understands.
Real feeds, counted honestly.
Plenty of tools advertise inflated list counts by counting dead or duplicate zones. Our catalog is 45+ curated, active sources, here is the actual breakdown.
A score you can put on a dashboard, and defend.
The 0-100 reputation score is deterministic and explainable. Every deduction traces back to a specific listing on a specific zone, weighted by severity and resolver confidence.
- Starts at 100, only confirmed listings deduct points
- Weighted deductions, list weight × severity × resolver confidence
- Signal boosts, a Google Safe Browsing hit costs 30 points; a high IPQualityScore fraud rating costs 20
- Noise-proof, inconclusive lookups add at most a 5-point uncertainty cap
- Trend history, score movements over time, with drop/rise alerts at your threshold
Rechecked on a schedule you choose.
Checks fire on add, on schedule and on demand. Scheduled cadence scales with plan.
| Trigger | When it runs | Notes |
|---|---|---|
| Initial scan | Immediately on adding an asset | Full catalog sweep, results in minutes |
| Scheduled recheck | Your interval, floored by plan: 30 min → every minute | Fastest cadence on Business and Enterprise |
| Manual re-scan | Any time, one click or bulk | Short cooldown between runs |
| Delisting confirmation | Automatic after a listing clears | Closes the loop without babysitting |
Blacklist status is one signal of several.
Monitoring protects a reputation. Something has to build it first, and something has to prove it is working.
Inbox Boost
Add a domain. We provision the sending server and publish your DNS.
Learn more FeatureInbox placement testing
See whether you land in Primary, Promotions or Spam across providers.
Learn more FeatureAlerts & integrations
Slack, email and signed webhooks, routed by your own rules.
Learn moreAll 45+ sources, searchable.
Not a curated sample. Search by name or DNS zone to check your specific problem list is covered, and see exactly how heavily each one counts against your score.
Each source carries a weight. A hit on Spamhaus ZEN takes more off your 0–100 score than a hit on a minor regional list, because receivers weight them differently too. These are the real deductions we apply.
Showing every source
| Source | DNS zone | Lists | For | Score impact |
|---|---|---|---|---|
| Spamhaus ZEN | zen.spamhaus.org | IPs | spam | −25Critical |
| Spamhaus DBL | dbl.spamhaus.org | Domains | spam | −25Critical |
| Spamhaus SBL | sbl.spamhaus.org | IPs | spam | −22Critical |
| Spamhaus XBL | xbl.spamhaus.org | IPs | malware | −20Critical |
| Spamhaus PBL | pbl.spamhaus.org | IPs | bulk | −10Medium |
| Spamhaus CSS | css.spamhaus.org | IPs | spam | −18High |
| Barracuda BRBL | b.barracudacentral.org | IPs | spam | −20Critical |
| SpamCop SCBL | bl.spamcop.net | IPs | spam | −18High |
| SORBS combined | dnsbl.sorbs.net | IPs | spam | −12High |
| SORBS Spam | spam.dnsbl.sorbs.net | IPs | spam | −10Medium |
| SURBL Multi | multi.surbl.org | Domains | spam | −20Critical |
| URIBL Black | black.uribl.com | Domains | spam | −20Critical |
| URIBL Red | red.uribl.com | Domains | spam | −15High |
| URIBL Grey | grey.uribl.com | Domains | spam | −10Medium |
| CBL Abuseat | cbl.abuseat.org | IPs | malware | −15High |
| Blocklist.de | bl.blocklist.de | IPs | abuse | −10Medium |
| UCEPROTECT Level 1 | dnsbl-1.uceprotect.net | IPs | spam | −8Medium |
| UCEPROTECT Level 2 | dnsbl-2.uceprotect.net | IPs | spam | −6Low |
| UCEPROTECT Level 3 | dnsbl-3.uceprotect.net | IPs | spam | −4Low |
| Backscatterer | ips.backscatterer.org | IPs | abuse | −6Low |
| NordSpam DBL | dbl.nordspam.com | Domains | spam | −10Medium |
| NordSpam IP | bl.nordspam.com | IPs | spam | −8Medium |
| SpamRats All | all.spamrats.com | IPs | spam | −10Medium |
| SpamRats NoPtr | noptr.spamrats.com | IPs | spam | −8Medium |
| SpamRats Dyna | dyna.spamrats.com | IPs | bulk | −6Low |
| Mailspike Black | bl.mailspike.net | IPs | spam | −12High |
| Mailspike Zero-Rep | z.mailspike.net | IPs | spam | −8Medium |
| PSBL | psbl.surriel.com | IPs | spam | −8Medium |
| IMP SpamRBL | spamrbl.imp.ch | IPs | spam | −6Low |
| Weighted Private BL | wpbl.pipex.net | IPs | spam | −6Low |
| DroneBL | dnsbl.dronebl.org | IPs | malware | −12High |
| AHBL | dnsbl.ahbl.org | IPs | spam | −4Low |
| Interserver RBL | rbl.interserver.net | IPs | spam | −6Low |
| Truncate | truncate.gbudb.net | IPs | spam | −8Medium |
| 0Spam | bl.0spam.org | IPs | spam | −6Low |
| Google Safe Browsing | gsb.googleapis.com | Domains | malware | −30Critical |
| Hostkarma White/Black | hostkarma.junkemailfilter.com | IPs | spam | −8Medium |
| JustSpam | dnsbl.justspam.org | IPs | spam | −6Low |
| s5h.net DNSBL | all.s5h.net | IPs | spam | −6Low |
| SpamEatingMonkey IPv4 | bl.spameatingmonkey.net | IPs | spam | −8Medium |
| SpamEatingMonkey URIBL | uribl.spameatingmonkey.net | Domains | spam | −8Medium |
| Spamhaus DQS AuthBL | authbl.dqs.spamhaus.net | IPs | spam | −22Critical |
| Spamhaus DQS ZRD | zrd.dqs.spamhaus.net | Domains | spam | −18High |
| Abusix Mail Intelligence | lookup.abusix.email | Both | spam | −18High |
| IPQualityScore | ipqs.io | Both | fraud | −20Critical |
| Cisco Talos Intelligence | talos.intel | Both | spam | −22Critical |
| Validity Certification | validity.com | Both | spam | −20Critical |
| SURBL Commercial API | api.surbl.org | Both | spam | −20Critical |
Generated from the same catalog the checking engine uses, so this list is what actually gets queried. Higher plans add the commercial feeds; the free tier already covers 41 of them.
Blacklist monitoring, explained.
How many blacklists are checked, exactly?
How is the 0-100 reputation score calculated?
When do checks actually run?
What happens when a listing is found?
Can I monitor sending IPs, not just domains?
Find out if you're listed, right now.
Your first scan runs the moment you add a domain. Free tier, no credit card.