Search & Browsing
crt.name subdomain finder
Trick
Type your domain into a crt.name web address and it lists subdomains on file for it. It needs no account or tools. Steps to do:
1. Pick the main domain you want to look up, like example.com (no www).
2. Open this address in your browser: https://crt.name/v1/search?apex=YOUR_DOMAIN
3. Replace YOUR_DOMAIN with your domain, for example https://crt.name/v1/search?apex=example.com
4. Press Enter. The page lists the subdomains crt.name has on file for that domain. A subdomain is a name in front of the main domain, such as blog.example.com.
5. Remember it is free and needs no account or API key.
6. It combines several sources, including certificate transparency logs, Common Crawl and ICANN zone files, which is why it finds so many names.
7. Check each name before trusting it. The list also includes old and dead names, so a name appearing doesn't mean the site still works.
8. Test each name yourself, for example by opening it in a browser, because crt.name does not check whether a host is reachable.
9. Only use this on domains you own or have permission to look into.
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