# dns-txt-mx-subdomain

> dns-txt-mx-subdomain is a paid API for AI agents from dns.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-20).

Looks up the TXT DNS record for the mx.<domain> subdomain via Cloudflare DoH and returns existence status, records, and TTL.

## Facts

- Endpoint: GET https://dns.intel.rallylive.ca/dns/host/mx/txt?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-txt-mx-subdomain-4e3a0652
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pHWOsr4G_3AdHftMLf6i9

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 dns-txt-mx-subdomain-4e3a0652
```

Example prompt: Can you check if mx.stripe.com has any TXT DNS records and tell me the TTL?

## When to prefer this

Use this endpoint when you need a quick, cheap ($0.01) existence check and TXT record retrieval specifically for the mx subdomain of a domain, without needing to enumerate all subdomains. Prefer this over generic DNS tools when you know you're targeting the mx host specifically and want a structured JSON response.

## Known failure modes

- Domain does not have an mx subdomain — returns non-existence result
- Domain is invalid or malformed — may return an error or empty result
- Cloudflare DoH is temporarily unavailable — lookup fails
- Domain has no TXT records on the mx subdomain — returns empty record set
- Rate limiting or payment failure — request rejected

## How this service works

TXT record of mx.<domain>: looks up the mx host under the domain you give (TXT via Cloudflare DoH) and reports whether it exists, its records and TTL. Quick existence check for common hosts like mx without enumerating subdomains. $0.01 per lookup.

## Output

Returns whether the mx.<domain> subdomain exists, its TXT record values (e.g. SPF, verification tokens, or other TXT strings), and the TTL of those records as resolved via Cloudflare DoH.

## 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/dns-txt-mx-subdomain-4e3a0652/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dns.intel.rallylive.ca](https://www.zero.xyz/host/dns.intel.rallylive.ca/llms.txt)