- 1Choose file
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- 3Download
Subdomain Finder online, free
Discover public subdomains for any root domain using Certificate Transparency (CT) logs safely and passively.
- Encrypted server job — auto-deleted in 24 h
- Free, no sign-up, no watermark
How to use Subdomain Finder · Subdomain Finder — frequently asked questions
How to use Subdomain Finder
- 1
Fine-tune the settings
The defaults already suit most files; change them only if you need to.
- 2
Run Subdomain Finder
Press the start button. The file is processed on an encrypted, auto-deleting server job.
- 3
Download the result
Save the finished file, or continue with another tool without downloading in between.
What Subdomain Finder can do
- Encrypted server processing; files are deleted automatically within 24 hours
- Free with no sign-up, no watermark and no daily limit
Subdomain Finder — frequently asked questions
How does the Subdomain Finder discover subdomains?
The tool queries public Certificate Transparency (CT) logs (such as crt.sh). Certificate Authorities are required by web standards to log every issued SSL/TLS certificate to public append-only logs, making it possible to discover public hostnames without brute-force scanning.
Is this method passive and non-intrusive?
Yes. Unlike aggressive DNS brute-forcing tools that bombard DNS servers with thousands of guesses, this query is 100% passive: it only queries public certificate transparency registries and sends zero traffic to the target domain.
Can this tool discover subdomains that do not use SSL certificates?
No. Because this tool queries cryptographic certificate logs, subdomains that have never requested or been issued an SSL/TLS certificate will not appear in the results.
Are wildcard certificates handled?
Yes. If an organization holds wildcard certificates (e.g., *.example.com), these entries are clearly tagged alongside specific subdomains (e.g., api.example.com, auth.example.com).
Does Sada Files retain or sell domain search history?
No. Queries are executed statelessly and never saved, tracked, or shared.
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