# Datakoot Subdomain Lookup

> Datakoot Subdomain Lookup is a paid API for AI agents from x402.datakoot.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).

Returns all known subdomains for a given registrable domain using certificate transparency log data from Cert Spotter (SSLMate).

## Facts

- Endpoint: POST https://x402.datakoot.com/api/subdomains?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/datakoot-subdomain-lookup-7c7475af
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-46lDJTDEKQroTFdAL140

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 datakoot-subdomain-lookup-7c7475af -d '<json body>'
```

Example prompt: Can you list all the subdomains for stripe.com using certificate transparency data?

## When to prefer this

Choose this endpoint when you need fast, certificate-transparency-based subdomain enumeration for a single domain and want pay-per-use pricing with no subscription. Prefer over DNS brute-force tools when you want passive, non-intrusive discovery. Prefer over manual Cert Spotter queries when integrating into an AI agent workflow with x402 micropayment support.

## Known failure modes

- Invalid or malformed domain input returns an error
- Domain with no certificate transparency records returns empty subdomains array
- Free tier cap limits results to 10 subdomains even if more exist (truncated=true)
- Payment failure on Base blockchain results in no charge and no response
- Rate limit exceeded on free MCP tier (100 calls/day)

## How this service works

48 live public-data tools (security, packages, SEC filings, economy, FX, weather, domains, Federal Register, Base) for AI agents. $0.002 USDC per call on Base via x402, charged only on success. The same tools are free for 100 calls/day via MCP at <server>.datakoot.com/mcp.

## Output

Returns a JSON object with the total subdomain count, the queried domain, the data source (Cert Spotter/SSLMate), an availability flag, a truncation flag indicating if results were capped, and an array of discovered subdomains. Free tier caps list results at 10 items per call.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "domain": {
   "type": "string",
   "description": "Registrable domain, e.g. stripe.com"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 16,
  "domain": "datakoot.com",
  "source": "Cert Spotter (SSLMate), first page of results",
  "available": true,
  "truncated": true,
  "subdomains": [
   "base.datakoot.com",
   "build.datakoot.com"
  ],
  "_datakoot_note": "Free tier: results capped at 10 items. Upgrade for full results at https://datakoot.com",
  "free_tier_note": "Shortened for the free tier: list results are capped at 10 items per call — subdomains (10 of 16). The counts in this re"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/datakoot-subdomain-lookup-7c7475af/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.datakoot.com](https://www.zero.xyz/host/x402.datakoot.com/llms.txt)