Subdomain Finder

Discover active subdomains using public SSL Certificate Transparency records

Certificate Transparency Subdomain Finder

Discover all public subdomains registered in SSL/TLS Certificate Transparency logs without port scanning

About This Tool

What is Certificate Transparency Subdomain Finder?

Discover all active and historical subdomains for any website using public SSL/TLS Certificate Transparency logs.

The Subdomain Finder leverages public Certificate Transparency cryptographic registries and DNS-over-HTTPS enumeration to map out your domain’s attack surface and discover subdomains without intrusive network brute-forcing.

Quick Guide

How to Use

1

Enter your root domain (e.g. example.com).

2

Click "Discover Subdomains".

3

Inspect the complete list of unique subdomains found in CT logs.

4

Review the issuing Certificate Authority and logged dates.

Advantages

Why Use This Tool?

Discover forgotten staging, dev, and admin subdomains

100% passive scan with zero origin IP exposure or port scanning

Inspect certificate issuers and validity periods

Prevent subdomain takeover vulnerabilities