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dns-a-smtp-subdomain
x402
dns-a-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 the A record for smtp.<domain> via Cloudflare DNS-over-HTTPS and reports whether the SMTP host exists, its IP records, and TTL.
Price / call$0.01
Success—
StatusUnknown
How this service works
A record of smtp.<domain>: looks up the smtp host under the domain you give (A 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 A record for smtp.<domain> exists, along with the resolved IP address(es), the TTL value, and the DNS response code — giving a quick picture of whether the SMTP subdomain is live and reachable.
Example use cases
Verify SMTP host before sending email
“Before I configure my mail client, can you check if smtp.fastmail.com has a valid A record in DNS and what IP it resolves to?”
Pre-flight check for new domain setup
“I just registered newstartup.io — can you check whether smtp.newstartup.io exists in DNS yet, so I know if my email server records have propagated?”
Audit third-party domain email infrastructure
“I need to vet a supplier before onboarding them — can you look up whether smtp.supplierdomain.com has an A record configured, and if so what the TTL is?”
Technical details
Endpoint
GEThttps://dns.intel.rallylive.ca/dns/host/smtp/a?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a fast, cheap ($0.01) existence check specifically for the smtp.<domain> subdomain via Cloudflare's reliable DoH resolver, without needing to enumerate or scan subdomains broadly. Ideal for email infrastructure validation, onboarding checks, or pre-flight configuration verification where only the A record of the smtp host matters.
Side effects
- Domain does not exist — NXDOMAIN response with no records
- smtp subdomain not configured — NOERROR but empty answer section
- Invalid or malformed domain input — API may return error or unexpected result
- Cloudflare DoH upstream timeout or outage — service may return error
- Network latency spike causing slow response
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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