# Subdomain Finder via Certificate Transparency

> Subdomain Finder via Certificate Transparency is a paid API for AI agents from intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Returns all subdomains of a given domain discovered in public TLS certificate transparency logs (crt.sh), deduplicated and sorted, up to 500 results.

## Facts

- Endpoint: GET https://intel.rallylive.ca/subdomains
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/subdomain-finder-via-certificate-transparency-4ec155cd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cyHnQjpU59lL9dukG-laJ

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 subdomain-finder-via-certificate-transparency-4ec155cd
```

Example prompt: Can you pull all the subdomains you can find for stripe.com using certificate transparency logs? I want to see everything that's shown up in public TLS certs.

## When to prefer this

Choose this endpoint when you need passive, non-intrusive subdomain enumeration based purely on public certificate transparency logs. It is ideal for OSINT, asset discovery, and attack-surface mapping without sending any traffic to the target. Prefer it over active DNS brute-force tools when stealth or legality is a concern, or when you need a quick, cheap ($0.01) snapshot of a domain's publicly known subdomains.

## Known failure modes

- Domain not found or never issued a TLS certificate returns an empty list
- Malformed domain input may return an error
- Rate limiting or payment failure returns a 402 response
- Results capped at 500 entries; very large domains may be truncated
- Wildcard certificate entries (e.g. *.example.com) may appear in results

## How this service works

Subdomain finder from certificate-transparency logs: every hostname under a domain that has appeared in public TLS certificates (crt.sh), deduplicated and sorted, up to 500. Attack-surface mapping, asset discovery and competitor research. $0.01 per domain.

## Output

A deduplicated, sorted list of up to 500 hostnames (subdomains) that have appeared in public TLS certificate transparency logs for the given domain, sourced from crt.sh.

## 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": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/subdomain-finder-via-certificate-transparency-4ec155cd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from intel.rallylive.ca](https://www.zero.xyz/host/intel.rallylive.ca/llms.txt)