Free Email Blacklist Checker
Check whether your domain or sending IP is listed on major email blacklists. Identify and fix deliverability blockers that are preventing your email from reaching the inbox.
How to Use This Tool
Enter your domain or IP
Type your sending domain (e.g. mailtani.com) or your outbound sending IP address. The tool checks against major blacklists used by inbox providers.
Review blacklist status
The tool shows which blacklists were checked and whether your domain or IP is listed on any of them.
Request delisting if listed
If you're listed, visit the blacklist's delisting page, fix the underlying issue (spam complaints, low authentication), and submit a removal request.
What Email Blacklists Are and How Inbox Providers Use Them
Email blacklists — formally called DNS-based Blackhole Lists (DNSBLs) or Realtime Blackhole Lists (RBLs) — are databases of IP addresses and domain names that have been identified as sources of spam, malware delivery, or other abusive email activity. They are operated by independent organisations and queried by mail servers as part of the spam filtering decision. When a mail server receives a connection, it looks up the sender's IP against one or more blacklists. If the IP is listed, the server can reject the message outright, quarantine it, or assign it a negative score that feeds into a broader spam filter calculation.
Inbox providers use blacklists as one input among many, not as a binary delivery gate. A listing on a minor or low-reputation blacklist may contribute a few negative points in a scoring system without causing outright rejection. A listing on Spamhaus's SBL or XBL — which are treated as high-confidence indicators of spam infrastructure or compromised hosts — is far more damaging and will cause delivery failures at many major inbox providers that explicitly reference Spamhaus data.
For senders on dedicated IPs, blacklist status is directly tied to your own sending behaviour and reputation. For senders on shared IP pools, your deliverability is partially dependent on the behaviour of other senders on the same IP. This is one of the practical arguments for dedicated IPs at higher send volumes: you gain control over your IP reputation even though you take on the responsibility of building it from scratch.
The Major Blacklists: What They Track and How They Work
Spamhaus operates the most widely referenced blacklists and is treated as authoritative by virtually every major inbox provider. The SBL (Spamhaus Block List) lists IPs and domains directly involved in spam operations. The XBL (Exploits Block List) lists IPs of compromised hosts — infected machines sending spam without the owner's knowledge. The PBL (Policy Block List) lists IP ranges that should not be sending direct-to-MX email, typically residential and dynamic IP ranges. A listing on any of these can cause immediate delivery failures at Gmail, Outlook, and Yahoo.
Barracuda Reputation Block List (BRBL) is heavily used by corporate mail gateways and hosted email security solutions. It is significant for B2B senders whose recipients use Barracuda email security products. SpamCop is fed by user complaints and being listed indicates your IP has received a high volume of spam complaints from active email users. SORBS maintains several sub-lists covering different categories of abuse. UCEPROTECT operates at three levels of increasing severity: Level 1 lists individual IPs, Level 2 lists entire network blocks, and Level 3 lists entire autonomous system numbers.
The practical approach is to check all major blacklists regularly but prioritise listings based on the blacklist's reach. A Spamhaus SBL listing requires immediate action. A UCEPROTECT Level 3 listing, which may result from a neighbouring IP in your ISP's network, is serious but requires different remediation than a self-caused listing.
How You Get Listed: Causes and Prevention
Getting listed on a blacklist almost always traces back to one of a small number of root causes. High spam complaint rates feed directly into complaint-based blacklists like SpamCop and indirectly into provider-side reputation scoring. The 2024 bulk sender requirements formalised 0.1 percent as a complaint threshold above which inbox providers begin restricting delivery, and 0.3 percent as a threshold for severe action. Keeping complaints low requires sending only to engaged recipients who explicitly opted in, honouring unsubscribes immediately, and never sending to purchased or scraped lists.
Sending to spam traps — email addresses used by blacklist operators to catch senders who do not maintain clean lists — is the other primary cause of blacklist listings. Pristine spam traps are addresses that have never been used to sign up for anything; receiving mail to them indicates you are sending to purchased, guessed, or harvested addresses. Recycled spam traps are old addresses that have been repurposed as traps after a period of inactivity. Sending to recycled traps indicates you are not removing long-term non-responders from your list.
Shared IP reputation is a less direct but significant cause of listings for senders on shared infrastructure. If other senders on your shared IP have high complaint rates or send to spam traps, the IP may be listed through no fault of yours. This is why monitoring your sending IP's blacklist status is important even if your own practices are clean — it gives you early warning of shared reputation problems that may require switching to a dedicated IP.
Delisting, Remediation, and Proactive Monitoring
The delisting process varies significantly by blacklist. Spamhaus requires investigation and acknowledgement of the root cause before manual review. Barracuda's BRBL has an automated delisting portal that processes requests within 12–24 hours for IPs that are no longer actively abusing. SpamCop listings expire automatically within 24 hours of the last spam report if no new reports arrive. UCEPROTECT notoriously charges for expedited delisting — which is widely considered extortionate; most practitioners advise waiting out the automatic expiry rather than paying.
Effective delisting requires addressing the root cause before submitting the request, not after. The root cause investigation should include: reviewing your sending practices, checking complaint rate data from your ESP's feedback loop, confirming that your list does not contain spam trap addresses, verifying that compromised systems are not sending mail without authorisation, and confirming that SPF, DKIM, and DMARC are all passing.
Proactive blacklist monitoring is the practice that prevents listings from becoming delivery crises. Check your sending IP and domain against the major blacklists daily if you send at scale, weekly if you send at lower volumes. Our blacklist checker automates this across all major lists simultaneously, returning results within seconds. Catching a listing immediately after it occurs — before a campaign send — allows you to investigate, remediate, and potentially delist before a single message is affected. Discovering a listing after a campaign has already gone out means your deliverability was compromised for that entire send.
Key Features
Multi-Blacklist Simultaneous Check
Queries all major DNSBLs including Spamhaus SBL, XBL, PBL, Barracuda, SpamCop, and SORBS in one request.
IP and Domain Coverage
Checks both sending IP addresses and domain names against lists that track each type separately.
Blacklist Severity Ranking
Ranks any found listings by deliverability impact, distinguishing major provider-used lists from minor ones.
Delisting Link Provided
For each blacklist where your IP or domain is listed, provides the direct delisting request URL.
Reverse IP Lookup Support
Automatically handles the reversed IP format required by DNSBL query syntax without manual reformatting.
Shared IP Context
Explains whether your sending infrastructure uses shared IPs and what that means for reputation exposure.
Frequently Asked Questions
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