Subdomain Explorer
Discover subdomains from Certificate Transparency logs via crt.sh
About this tool
Find subdomains from crt.sh CT logs. Passive OSINT only — no DNS brute force. Free, no signup. Subdomain Explorer runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.
What this tool does not do
- Subdomain Explorer is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.
How do I use this tool?
How do I use Subdomain Explorer?
Open Subdomain Explorer, enter or paste your input, and copy the result. The page works without an account.
Related guides
Related tools
API Mock Server
Define mock REST routes and intercept fetch calls client-side
Bandwidth Calculator
Estimate how long a file takes to transfer at a given connection speed — correctly handling bits vs bytes (Mbps vs MB/s) and SI vs binary size units
Broken Link Checker
Extract http(s) links from pasted HTML and check them via proxy
cURL to Code Converter
Convert cURL commands to code snippets in multiple languages. Parse cURL and generate JavaScript, Python, PHP, and more.
DNS Lookup Tool
Query DNS records and resolve domain names to IP addresses
DNS Propagation Checker
Compare DNS answers from global public resolvers and see propagation consensus instantly