This tool allows to find subdomains and other related domains for a given domain name. The tool searches through the public Certificate Transparency Logs (CTLs), which is a list of all SSL certificates that have been issued.
Subdomains
When a certificate is issued for a subdomain of the given domain, the subdomain is shown here.
Related domains
An SSL certificate can be issued for multiple domains at the same time, if the person requesting them has control over both domains.
When a certificate is issued for the domain and another different domain, this different domain is shown here.
Expired certificates
Note: if there is a large amount of certificates for a domain name, this result set might not show the latest certificate for that domain name, but an older certificate instead. The expiry date shown is then incorrect.