# DNS TXT Record Lookup for smtp Subdomain

> DNS TXT Record Lookup for smtp 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 2026-10-21).

Looks up TXT DNS records for the smtp.<domain> subdomain via Cloudflare DNS-over-HTTPS and returns existence status, records, and TTL

## Facts

- Endpoint: GET https://dns.intel.rallylive.ca/dns/host/smtp/txt?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-txt-record-lookup-for-smtp-subdomain-0d088540
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vxTmeGOqpd_K9ube-UPwT

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-record-lookup-for-smtp-subdomain-0d088540
```

Example prompt: Can you check if there's a TXT record configured for the smtp subdomain of example.com — I want to know if smtp.example.com exists in DNS and what its records and TTL are?

## When to prefer this

Use this endpoint when you need a quick, targeted check on whether the smtp host under a given domain has TXT DNS records, without enumerating all subdomains. Prefer this over general DNS lookups when specifically investigating email-related subdomain configuration or verifying SMTP infrastructure presence at low cost ($0.01 per lookup).

## Known failure modes

- Domain does not exist — returns NXDOMAIN with no records
- smtp subdomain has no TXT records — returns empty record set
- Malformed domain input — may return error or empty result
- Cloudflare DoH unavailable — request may time out
- Rate limiting or payment failure — 402 response if funds not available

## How this service works

TXT record of smtp.<domain>: looks up the smtp 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 smtp without enumerating subdomains. $0.01 per lookup.

## Output

Returns whether the smtp.<domain> subdomain has TXT records, the content of those records if they exist, the TTL, and the DNS response code (e.g. NOERROR, NXDOMAIN). Answered by Cloudflare DNS-over-HTTPS.

## 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-record-lookup-for-smtp-subdomain-0d088540/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)