# Certificate Transparency Subdomain Lookup

> Certificate Transparency Subdomain Lookup is a paid API for AI agents from pyfile-agent.taile3ff35.ts.net:10000, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-13).

Queries crt.sh to return all subdomains discovered for a given domain via certificate transparency logs

## Facts

- Endpoint: GET https://pyfile-agent.taile3ff35.ts.net:10000/data/ct
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/certificate-transparency-subdomain-lookup-37b8863a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3g6m3taWq0C6tMsvExWjO

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability certificate-transparency-subdomain-lookup-37b8863a
```

Example prompt: Can you pull all the subdomains that have been logged for example.com using certificate transparency records?

## When to prefer this

Use this endpoint when you need passive subdomain enumeration for a domain without sending any traffic to the target — certificate transparency logs are public and comprehensive. Prefer this over active DNS scanning when stealth or read-only reconnaissance is required. It is especially useful for security audits, asset discovery, and verifying your own domain's certificate issuance history.

## Known failure modes

- Missing or empty 'domain' query parameter returns an error or empty result
- Invalid or nonexistent domain returns empty subdomain list
- crt.sh upstream timeout or unavailability causes request failure
- Rate limiting on crt.sh may cause intermittent failures
- Very large domains with thousands of certificates may return truncated results

## How this service works

Certificate transparency subdomains (crt.sh). ?domain=example.com

## Output

Returns a list of subdomains (hostnames) discovered for the queried domain from certificate transparency logs aggregated by crt.sh, potentially including historical and currently active subdomain entries tied to issued SSL/TLS certificates.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "domain": {
       "type": "string"
      }
     }
    }
   }
  },
  "output": {
   "type": "object"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/certificate-transparency-subdomain-lookup-37b8863a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pyfile-agent.taile3ff35.ts.net:10000](https://www.zero.xyz/host/pyfile-agent.taile3ff35.ts.net%3A10000/llms.txt)