10 Top Blacklist Checkers in 2026

Introduction

Spam accounts for nearly half of all email traffic, around 47% globally in 2024, according to Statista, which is why blacklists exist in the first place. However, not all blacklists carry the same weight. Some can significantly affect deliverability. Many have little to no impact on whether your emails reach the inbox. 

Gmail and Microsoft, which handle the majority of business email worldwide, rely primarily on their own reputation systems built around engagement, authentication, complaint rates, and sending behavior. That's why it's entirely possible to be listed on several blacklists and still reach the inbox, or appear clean everywhere and land in spam.

In this guide, instead of ranking tools by how many blacklists they check, we try to answer which blacklists actually matter, along with a breakdown of the best blacklist checkers for different use cases.

We'll also cover what to do after a listing is found, how to approach delisting properly, and why blacklist status is only one piece of the deliverability puzzle.

Quick Comparison: Best Blacklist Checkers in 2026 at a Glance

Most blacklist checkers look similar on the surface, but they differ significantly in what they check, how they monitor, and whether they help beyond a simple blacklist lookup. The table below compares the leading options side by side before we get into the detailed reviews. 

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Which Blacklists Actually Matter? The Severity Tier List

Evaluating a blacklist checker by how many lists it scans is often the wrong metric because 99% of public blacklists have little to no influence on Google Workspace or Microsoft. 

Google and Microsoft use their own reputation systems built around engagement, content quality, authentication, complaint rates, and sending behavior. Public blacklists sit outside those systems.

As a result, being listed on the wrong blacklist often doesn't matter, while being listed on the right one absolutely does. That's why the more useful question isn't "How many blacklists does this tool check?" but "Which blacklists are actually worth paying attention to?" The tier list below answers exactly that.

Spamhaus is the exception to the "most blacklists don't matter" rule. If you're listed on Spamhaus, pay attention. Its data protects billions of mailboxes worldwide and is widely referenced across the email ecosystem. 

A Spamhaus listing is usually a sign of a real sending problem that needs to be fixed, not ignored. Barracuda BRBL is the next most important blacklist, with meaningful adoption across enterprise email-security deployments.

UCEPROTECT sits at the opposite end of the spectrum. Its Level 2 and Level 3 listings can flag entire IP ranges based on the behavior of other senders sharing the same infrastructure.

It means perfectly legitimate senders can appear on the list despite doing nothing wrong because Gmail and Outlook don't use UCEPROTECT for inbox-placement decisions, a listing rarely has any practical impact. In most cases, the right move is to wait for auto-expiry and focus on the signals that actually influence deliverability.

10 Best Blacklist Checkers in 2026

The best blacklist checker depends on the problem you’re trying to solve. Some tools are designed for quick blacklist lookups, while the others help monitor listings over time. A few go beyond blacklist status entirely and help diagnose the deliverability issues that usually sit underneath it. Here's how a few options compare. 

1. MailReach

MailReach is a B2B email deliverability platform that helps businesses improve inbox placement through email warmup and spam testing. It enables users to build sender reputation, monitor deliverability, verify SPF, DKIM, and DMARC authentication, and test where emails land across providers such as Gmail, Outlook, Google Workspace, and Microsoft 365. 

Key features:

• Inbox Placement Testing: Sends a real email to seed inboxes across Gmail, Outlook, Google Workspace, and Microsoft 365 to show where messages actually land. Helps identify deliverability issues that blacklist checks and content scanners cannot detect.
• Email Warmup Network: Builds sender reputation through ongoing positive engagement on a network of 30k+ mailboxes composed largely of real Google Workspace and Office 365 providers. Helps improve inbox placement with the providers that matter most for B2B outreach.
• Authentication Verification: Tests SPF, DKIM, and DMARC under real receiving conditions rather than simply checking DNS records. Helps uncover configuration and alignment issues that can affect inbox placement and sender trust.
• Reputation Monitoring: Tracks sender reputation by domain, provider, and campaign segment, making it easier to spot deliverability declines before they become spam-folder placement or blocking problems.
• Deliverability Diagnostics: Combines blacklist checks, spam-word analysis, link inspection, and content evaluation in a single report. Helps pinpoint the specific factors affecting inbox placement instead of relying on a single deliverability metric.

Pricing: MailReach's All-In-One plan starts at $25 per mailbox/month and includes automated email warmup, 20 spam test credits, reputation tracking, authentication checks (SPF, DKIM, DMARC). 

Pros:

• Goes beyond blacklist checking to show actual inbox placement at Gmail, Outlook, and Office 365
• End-to-end authentication testing catches misconfigurations DNS-only tools miss
• Content diagnostics (links, spam words, tracking pixels) in every test
• Built for B2B cold outreach across Google Workspace and Office 365
• Also offers warmup to fix the underlying reputation issue that often drives spam placement

Best for: B2B sales teams, growth marketers, founders, and lead-gen agencies 

2. MXToolbox

MXToolbox is a free blacklist lookup and email diagnostics tool that checks an IP or domain against 100+ public DNS-based blacklists (DNSBLs) in a single query. Alongside the blacklist scan, it runs MX, DNS, SMTP, and email-header diagnostics, which makes it a general mail-server troubleshooting suite rather than a blacklist-only tool. 

Key Features: 

• Multi-Blacklist Lookup: Checks a domain or sending IP against 100+ public DNSBLs in a single query and returns color-coded results in seconds. Helps senders confirm quickly whether their infrastructure has been flagged anywhere that matters.
• SuperTool Diagnostics: Combines MX, A, PTR, SPF, DKIM, DMARC, SMTP, and blacklist checks into one search interface with clear pass/fail output. Helps administrators run a full infrastructure health check without jumping between separate tools.
• Delivery Center Monitoring: Continuously monitors blacklist status and sender health across multiple domains and sends real-time alerts when something changes. Helps teams catch a blacklisting event immediately instead of discovering it after deliverability has already dropped.
• DMARC Report Aggregation: Collects and parses DMARC aggregate reports on paid plans so authentication and spoofing data is readable rather than raw XML. Helps organizations tighten authentication policies and spot domains sending without permission.

Pros:

• Industry-standard, fast, trusted by sysadmins.
• Checks 100+ blacklists in one lookup.
• Broad diagnostic suite beyond blacklists.
• Free for one-time lookups.

Cons:

• No severity ranking, a low-impact listing looks as alarming as a Spamhaus hit.
• No remediation or delisting guidance.
• Monitoring and API are paid and get expensive for small teams.
• DNS-only checks can miss real-world authentication failures.

Pricing: MXToolbox offers a free plan with weekly blacklist monitoring for one domain. Paid plans start at $129/month (Delivery Center) and $399/month (Delivery Center Plus) 

Best for: IT admins and sysadmins who need a trusted lookup tool and can read raw results without a severity guide. 

3. Spamhaus Lookup

Spamhaus is a nonprofit threat intelligence organization whose free IP and Domain Reputation Checker confirms whether an IP address, domain, email address, or hash appears on any Spamhaus DNS blocklist. 

The checker queries the project's own datasets, including the Spamhaus Blocklist, Exploits Blocklist, Combined Spam Sources list, Policy Blocklist, and Domain Blocklist, then reports each listing in the order it must be resolved. 

Key Features

• Multi-Identifier Lookup: Accepts IPv4, IPv6, domains, email addresses, and hash strings in one search field. Helps any user check the exact resource that may be causing delivery problems without picking the right tool first.
• Spamhaus Dataset Coverage: Checks against the SBL, XBL, CSS, PBL, and DBL, the blocklists most widely used by mailbox providers and filters. Helps senders see their standing on the lists that have the largest real-world impact on inbox placement.
• Removal-Order Results: Lists multiple flags in the sequence they must be cleared, since some listings block delisting from others until resolved. Helps users fix problems in the correct order instead of chasing dead ends.
• Auto IP Detection & Tooltips: Automatically detects the visitor's IP and adds inline tooltips for less technical users. Helps non-specialists understand and act on a listing without outside help.

Pros:

• Checks the most influential and widely trusted blocklists in email.
• Completely free and run by a long-established nonprofit.
• Clear, ordered delisting and troubleshooting guidance.
• Handles IPs, domains, emails, and hashes from one search box.

Cons: 

• Only checks Spamhaus's own lists, not other RBLs.
• The free checker offers no ongoing monitoring or alerts.
• SBL removals often require your ISP to act, not you directly.
• Built for one-off diagnosis rather than continuous tracking.

Best for: Any sender who needs to confirm a Spamhaus listing and follow the correct removal steps, and teams that prioritize standing on the blocklists with the heaviest influence on deliverability. 

4. Hetrix Tools

HetrixTools is a monitoring service that combines uptime monitoring with IP and domain blacklist monitoring in a single platform. Its blacklist monitor checks IP addresses and domains against major DNSBLs at scheduled intervals, sends alerts through email, webhook, Telegram, and other channels when a listing appears, and provides dynamic delisting links and shareable reports. 

Key Features

• Blacklist Monitoring: Continuously checks your IPs and domains against major DNSBLs and flags any new listing automatically. Helps operators catch reputation problems early before they turn into widespread delivery failures.
• Dynamic Delisting Links & Reports: Generates direct delisting links for flagged listings and shareable status reports. Helps agencies and hosts both fix issues quickly and show clients a clean reputation record.
• Combined Uptime + Blacklist Monitoring: Tracks server and network uptime alongside blacklist status from the same dashboard. Helps infrastructure teams consolidate two monitoring needs into one affordable platform.
• API & On-Demand Checks: Offers an API and manual on-demand blacklist checks across all monitors. Helps developers automate reputation monitoring and run instant checks when investigating an incident.

Pros:

• Generous free tier covering 32 monitors.
• Among the cheapest paid blacklist monitoring available.
• Combines uptime and blacklist monitoring in one tool.
• Shareable client reports plus a usable API and multi-channel alerts.

Cons:

• Free monitors are paused for inactive accounts.
• Support is slower for free users.
• The interface is functional rather than polished.
• No inbox placement testing, purely reputation and uptime focused.

Pricing: HetrixTools offers separate plans for uptime and blacklist monitoring. Uptime monitoring starts free (15 monitors) and scales to $49.95/month for 200 monitors. Blacklist monitoring starts free (32 monitors) and scales to $99.95/month for 8,192 monitors. 

Best for: MSPs, small businesses, and sysadmins who need ongoing blacklist monitoring without a budget for enterprise tools

5. MultiRBL

MultiRBL is a free multiple DNSBL lookup and Forward Confirmed reverse DNS check tool hosted at multirbl.valli.org. It tests a single IPv4 or IPv6 address against more than 200 blacklists, whitelists, and informational lists at once, returning each result color-coded so users can separate genuine blocklistings from neutral entries that do not affect delivery. 

Alongside reputation lookups, it runs an FCrDNS check that verifies whether an IP's reverse DNS pointer resolves back to the same address, a common requirement for mail acceptance. 

Maintained independently and supported by donations, MultiRBL prioritizes breadth of coverage and technical detail over dashboards, accounts, or automated monitoring. 

Key features:

• 200+ List Coverage: Tests an IP against more than 200 blacklists, whitelists, and informational lists in a single lookup. Helps technical users get the widest possible reputation picture from one query.
• FCrDNS / iprev Check: Verifies that an IP's reverse DNS pointer resolves forward back to the same address. Helps diagnose a common cause of mail rejection that pure blacklist checks miss entirely.
• Color-Coded Results: Distinguishes blacklist hits, whitelist entries, and neutral informational listings using clear color coding. Helps users avoid panicking over neutral entries that have no effect on delivery.
• IPv4 and IPv6 Support: Checks both IPv4 and IPv6 mail server addresses. Helps operators on modern infrastructure verify reputation for the address their server actually sends from.

Pros:

• Extremely broad coverage, including whitelists and neutral lists.
• Built-in FCrDNS check most blacklist tools lack.
• Clearly separates real blocklistings from informational entries.

Cons:

• Dense, technical interface that can overwhelm beginners.
• No monitoring, alerts, or saved history.
• No API or bulk checking.
• Maintained by an individual and funded by donations.

Pricing: Free

Best for: Technical email administrators who want the widest possible one-shot RBL coverage plus an FCrDNS check, and who are comfortable interpreting dense results 

6. DNSChecker.org

DNSChecker is a free online toolkit of DNS, network, and email utilities, one of which is an IP blacklist checker that tests a domain, IP address, or email against more than 50 anti-spam databases. 

The blacklist tool runs real-time DNS queries and returns results in roughly 20 to 40 seconds, indicating which DNSBLs have flagged the address along with delisting references. It requires no signup and sits beside related utilities such as MX lookup, DMARC validation, SMTP test, and reverse DNS, allowing users to diagnose several deliverability factors from one site. 

Key Features:

• 50+ Blacklist Lookup: Checks an IP, domain, or email against more than 50 anti-spam databases in real time. Helps users quickly see whether their sending address has been flagged anywhere common.
• Multi-Resource Input: Accepts domains, IP addresses, and email addresses for blacklist checks. Helps senders test the specific identifier they suspect is causing delivery issues.
• Broader DNS Toolkit: Sits alongside MX lookup, DMARC validation, SMTP test, reverse DNS, and dozens of other free utilities. Helps users diagnose multiple deliverability factors without leaving the site.
• Delisting References: Indicates which databases flagged the address and points toward delisting resources. Helps senders move from diagnosis to remediation in the same workflow.

Pros:

• Bundled with a large free DNS and network toolkit.
• Checks IPs, domains, and email addresses.
• Simple, beginner-friendly interface.

Cons:

• Ad-supported pages.
• Fewer lists than dedicated blacklist tools (50+).
• No monitoring, alerts, or blacklist API.
• Strictly one-off checks, not continuous tracking.

Pricing: Free

Best for: Anyone who wants quick, free, ad-hoc blacklist checks alongside general-purpose DNS and email lookups in a single place. 

7. BlacklistChecker.com

Blacklist Checker is a tool that tests any IP address, domain name, or email address against more than 100 email blacklists, also known as DNSBLs or RBLs. The free web checker returns results in seconds, showing which lists have flagged the address so senders can identify why messages may be rejected or filtered. 

Key Features:

• 100+ Blacklist Coverage: Tests an IP, domain, or email against more than 100 DNSBLs and RBLs in one check. Helps senders confirm their standing across the lists most filters actually query.
• Developer API: Provides a fast, easy-to-use REST API for programmatic blacklist checks on IPs, domains, and emails. Helps developers build blacklist verification directly into their own apps or onboarding flows.
• Daily Monitoring & Alerts: Rechecks saved addresses daily and notifies you when a new listing appears. Helps teams stay ahead of reputation drops without manually re-running checks.
• Multi-Resource Input: Accepts IP addresses, domain names, and email addresses. Helps users pinpoint exactly which identifier is triggering delivery problems.

Pros:

• Free, instant web checks with no account.
• Checks IPs, domains, and email addresses.
• Clean, developer-friendly API for integration.
• Optional daily monitoring with alerts.

Cons:

• Monitoring and API access sit behind paid plans.
• Fewer native integrations than full deliverability suites.
• Not a sending, warmup, or inbox-placement platform.
• Confirm current paid pricing directly on their site, as tiers vary by usage.

Pricing: Blacklist Checker offers a free plan with 50 checks per month. Paid plans start at $9/month for 10,000 checks, $39/month for 50,000 checks, and $149/month for 250,000 checks. 

Best for: Developers who want to embed blacklist checks via API, and teams that want lightweight automated monitoring without a heavier deliverability platform. 

8. ZeroBounce

ZeroBounce is an email validation and deliverability platform that verifies whether email addresses are real, active, and safe to send to, then layers on tools that improve inbox placement. 

Its core engine performs bulk and real-time validation, detecting invalid addresses, spam traps, and abusive recipients, and assigns AI-based quality scores.  

Key Features:

• AI Email Scoring: Assigns a quality and engagement score to addresses that pass validation. Helps teams prioritize the most likely-to-engage contacts rather than treating every valid address equally.
• Deliverability Toolkit: Bundles inbox placement testing, blacklist monitoring, email warmup, and server testing. Helps senders see where mail actually lands and improve it, not just clean the list.
• DMARC Monitor: Tracks DMARC reports and authentication alignment for sending domains. Helps organizations harden authentication and detect spoofing that hurts trust.
• Email Finder & Data Tools: Finds and appends contact data, including an Email Finder that costs credits per successful query. Helps sales and marketing teams build and enrich lists from the same platform.

Pros:

• High validation accuracy with broad spam-trap and abuse detection.
• All-in-one suite spanning validation, deliverability, and prospecting.
• 100 free validations every month and credits that never expire.
• Unused subscription credits roll over indefinitely.

Cons:

• Costs scale quickly as validation volume grows.
• Inbox placement and blacklist monitoring require the ZeroBounce ONE bundle or higher.
• Email Finder consumes 20 credits per successful query.

Pricing: ZeroBounce offers a free plan with 100 validation credits/month, 1 inbox placement test, and 1 blacklist monitor. Paid plans start at $99/month (minimum 10,000 credits)

Best for: Marketers and businesses that need accurate list cleaning and also want inbox placement testing, blacklist monitoring, and warmup combined in one platform. 

9. Mailtrap

Mailtrap is an email delivery platform that combines a production sending service with a safe testing sandbox for developers and product teams. The Email Sending side provides API and SMTP delivery with SPF, DKIM, and DMARC authentication, separate transactional and bulk streams, bounce and complaint suppression, and detailed logs and analytics. 

The Email Sandbox captures messages in an isolated environment, running spam-score and inbox placement tests across providers like Gmail, Outlook, Apple, and Yahoo and validating HTML before anything reaches real recipients.

Key Features: 

• Email Sandbox Testing: Captures outgoing email in an isolated environment and runs spam-score and inbox placement tests across Gmail, Outlook, Apple, and Yahoo without sending to real inboxes. Helps teams catch deliverability and rendering problems safely during development and QA.
• Email Sending API & SMTP: Delivers transactional and bulk email through a developer-friendly API or SMTP relay with prebuilt SDKs. Helps engineering teams integrate reliable sending quickly with minimal setup.
• HTML & Spam Analysis: Inspects message HTML and assigns spam scores before delivery. Helps developers fix broken markup and spam triggers that quietly hurt inbox placement.

Pros:

• Developer-friendly API, SMTP, and SDKs with fast setup.
• Safe sandbox for spam-score, HTML, and inbox placement testing pre-send.
• Strong authentication plus separated transactional and bulk streams.

Cons:

• Sandbox testing and production sending are billed separately.
• Not a dedicated blacklist or RBL monitoring tool.
• Built more for developers than non-technical marketers.
• Deliverability monitoring depth is limited versus specialized platforms.

Pricing: Mailtrap offers separate plans for Email Sandbox and Email API/SMTP. Sandbox testing starts free (50 test emails/month) and scales to $498/month. Sending plans start free (4,000 emails/month), with paid tiers from $15/month to $750/month

Best for: Developers, SaaS, and QA teams that send transactional and bulk email and want to test deliverability before launch while sending reliably at scale. 

10. SpamCop

SpamCop is a spam-reporting service operated by Cisco Talos that maintains the SpamCop Blocking List, a real-time DNS blacklist of IP addresses currently sending reported spam. The list is built from user-submitted spam reports and hits on SpamCop-operated spam traps, which are weighted by recency and volume before an IP is added. 

Key features:

• Real-Time SCBL: Maintains a live blocklist of IPs currently sending reported spam, focused on present activity rather than historical offenses. Helps filtering operators block active spam sources as they emerge.
• Automatic Time-Based Delisting: Removes an IP automatically about 24 hours after reports stop, with no manual delist form. Helps legitimate senders recover quickly once the underlying spam is fixed.
• Free IP Lookup: Lets anyone check whether an IP is on the SCBL through a free lookup on spamcop.net. Helps senders confirm an SCBL listing when troubleshooting a bounce.
• DNSBL Query Integration: Lets mail servers query bl.spamcop.net during the SMTP transaction to block or tag mail. Helps administrators plug the list into existing spam-filtering pipelines.

Pros:

• Free to query and widely integrated into mail filters.
• Real-time focus on IPs actively sending spam.
• Automatic delisting within about 24 hours once reports stop.

Cons:

• Aggressive listing logic can produce false positives.
• Lists IP addresses only, not domains or email addresses.
• No manual removal. You must fix the root cause and wait.
• Shared-IP senders can be listed for someone else's behavior.

Pricing: Free to check and to use as a DNSBL.

Best for: Mail administrators and filtering operators who use the SCBL as one signal in a scoring system, and senders checking or clearing an active SpamCop listing.

How to Check If Your IP or Domain Is Blacklisted (Step-by-Step)

Before you start troubleshooting deliverability issues, you need to confirm whether your sending IP or domain is actually listed on a blacklist. Here’s a simple step-by-step process to check your blacklist status and identify potential reputation problems.

Step 1: Find Your Real Sending IP and Domain

Start with the IP your emails leave from. If you send through Gmail or Google Workspace, that IP isn't really yours.

Google's infrastructure handles delivery, so there's no server IP of your own to look up. On a transactional ESP like SendGrid, Mailgun, Amazon SES, Postmark, or Brevo, your mail goes out on the provider's shared or dedicated ranges (their docs list the current ones). 

The quickest way to find the real one is to send yourself a test email, open the headers, and read the Received: lines for the sending IP.

Then grab your sending domain, the domain in your From: address. You'll need both for what comes next.

Step 2: Check the Tier 1 Blacklists First

Run your IP and domain against Spamhaus directly at check.spamhaus.org, then against Barracuda (BRBL). These are the Tier 1 sources that the inbox providers actually rely on. If you're clean on both, you've already ruled out the listings most likely to be hurting you, without drowning in dozens of low-impact lists.

Step 3: Run an Aggregator for the Bigger Picture

Clean on Tier 1 but still seeing problems? Now it's worth casting a wider net. Run a lookup through MXToolbox, MultiRBL, or DNSChecker.org to scan a much larger set of lists in one go.

Just read the results with a clear head. A Spamhaus or Barracuda hit means act now. A UCEPROTECT Level 3 listing? Usually noise, most providers ignore it, and so can you.

Step 4: Check Both Your IP and Your Domain

IP blacklists (like Spamhaus SBL) flag the server your mail sends from. Domain blacklists (like Spamhaus DBL) flag the domain in your From: address. They're separate lists, and you can easily be clean on one while listed on the other.

Step 5: Test Where Your Emails Really Land

A clean blacklist report tells you about external databases, but doesn’t tell you about where Gmail and Outlook are putting your emails right now.

The only way to know that is an inbox placement test, sending a real email, under your real sending conditions, to a set of real mailboxes (including Google Workspace and Office 365 inboxes) and seeing exactly where each one lands.

That's what MailReach's free spam test does in a single run. It checks inbox placement end to end, verifies your SPF, DKIM, and DMARC, scans your content and links, so you're not stitching five tools together. 

Special Case: Shared IP Blacklisting

If you're sending through a shared IP, your reputation is tied to everyone else using that same infrastructure. One sender generating complaints, hitting spam traps, or sending low-quality mail can get the IP listed, and everyone sharing it feels the impact.

When that happens, you have a few options:

• Ask your provider to move you to a different IP pool.
• Upgrade to a dedicated IP if your sending volume justifies it.
• Switch to an ESP with stronger reputation management and cleaner shared IP pools.

For cold outreach, though, the better long-term approach is often to reduce your dependence on shared sending infrastructure altogether. Sending through Google Workspace or Microsoft 365 gives you access to highly trusted mail systems while allowing you to build reputation around your own domain rather than a shared IP pool.

If you're on a shared IP, investigate the source of the listing before assuming your own sending practices caused it.

How to Choose the Right Blacklist Checker for Your Situation

The best blacklist checker depends on what you're trying to accomplish. Some tools are built for quick lookups, while others focus on monitoring, automation, deliverability analysis, or email validation.

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Choosing a Blacklist Checker in 2026

For B2B senders, blacklist status answers a narrow question ("is this IP or domain flagged by external DNSBLs?"). Inbox placement testing answers the broader one ("where do my emails actually land at Gmail, Outlook, and Office 365?"). 

A clean blacklist record doesn't guarantee inbox placement. A listing on a Tier 4 source doesn't preclude it. MailReach's free spam test bundles blacklist checking with real inbox placement testing, end-to-end authentication checks, content analysis, and per-provider reporting, covering the full diagnostic in one step instead of stitching together five tools.

Stop guessing. See exactly where your emails land at Gmail, Outlook, and Office 365 with MailReach