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CT Subdomain Enumeration
x402
CT Subdomain Enumeration is a paid API for AI agents from anibalb.duckdns.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).
Enumerates subdomains for a given domain by querying Certificate Transparency logs, returning discovered subdomains along with their TLS certificate issuers.
Price / call$0.002
Success—
StatusUnknown
How this service works
Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.
Output
Returns a JSON object containing the queried domain and an array of discovered subdomains, each with the subdomain's full hostname and the name of the TLS certificate issuer (e.g. Let's Encrypt, DigiCert) that issued a certificate for it.
Example use cases
Attack surface mapping for security audit
“I'm doing a security assessment on acmecorp.com — can you pull all discovered subdomains from certificate transparency logs so I can map out their full attack surface?”
Competitive domain intelligence gathering
“I want to see what subdomains competitor.com has exposed publicly — can you enumerate them via CT logs and list the certificate issuers?”
Monitoring for unexpected subdomains
“Can you check what subdomains are registered under mybrand.com in the certificate transparency logs? I want to make sure there are no unexpected or unauthorized subdomains showing up.”
Technical details
Endpoint
GEThttps://anibalb.duckdns.org/x402/ct-subdomain-enum?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need passive, non-intrusive subdomain discovery based on Certificate Transparency log data — it requires no active scanning of the target domain and is suitable for recon, security audits, or attack surface mapping. Prefer this over active DNS brute-force tools when stealth or read-only access is required, and when you want to find subdomains that have had TLS certificates issued rather than guessing names.
Side effects
- Domain not found in CT logs returns empty subdomains array
- Invalid domain format may return an error or empty result
- CT log data may be incomplete or delayed for very new domains
- Rate limiting or payment failure returns 402 Payment Required
- Wildcard certificates may obscure individual subdomains
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"domain": "example.com",
"subdomains": [
{
"name": "www.example.com",
"issuer": "Let's Encrypt"
}
]
}
}Tags
x402
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