Domain Blacklist Checker
Check a domain and its mail servers against real public spam blacklists (DNSBLs) — no vendor score, just real listings.
A site's technical health — DNS, TLS, redirects, response headers, how fast the page actually loads — rarely gets noticed until something breaks. These checks look at exactly what a browser or a mail server would see, so a problem shows up here before a visitor (or a customer) finds it first.
Running the Domain Blacklist Checker fetches only the URL you give it, the same way a browser or a search engine's crawler would, and reports back what it finds. Nothing about the check is saved once the result is on your screen.
There's no right moment to reach for the Domain Blacklist Checker — some people run it once before shipping something, others keep it open and use it every day. Either way, it stays free, there's no limit on repeat use beyond a light rate limit, and nothing about a previous run is remembered the next time you open the page. It's also one of several tools in the Website category here, so if it turns out not to be quite the right one, the related tools listed below are worth a look before searching elsewhere.
Common questions
Does this tool store the URLs I check? No accounts, no history, no saved reports. Each check runs fresh and nothing about it is kept after the response is sent back to your browser.
Can I use this on a site that isn't live yet? It needs to be reachable over the public internet to check it, so a site only available on localhost or a private network won't work.
Why might the result differ from another checker? Different tools query different resolvers, servers or vantage points, so small differences in timing or record order are normal — what matters is whether the underlying facts agree.
Related Website tools
A few other website tools people tend to reach for alongside the Domain Blacklist Checker: