# PennyRail MX DNS Records Lookup

> PennyRail MX DNS Records Lookup is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Performs an MX (Mail Exchange) DNS record lookup for a given domain, returning its mail server records

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/dns.records--mx-lookup
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-mx-dns-records-lookup-80c9c8a7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LUUtCQDA5AVJcYDeckX7V

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 pennyrail-mx-dns-records-lookup-80c9c8a7 -d '<json body>'
```

Example prompt: Can you look up the MX records for example.com so I can see which mail servers handle its incoming email and their priority values?

## When to prefer this

Use this endpoint when you need a pay-per-call, programmatic MX DNS lookup with no subscription or API key required, especially in agent workflows where x402 micropayment settlement is already in use. Prefer over free DNS tools when operating within a PennyRail or x402-enabled payment pipeline.

## Known failure modes

- Domain does not exist or has no MX records — returns empty record set or DNS NXDOMAIN error
- Malformed or missing input domain — may return 400-level validation error
- DNS resolution timeout — upstream resolver may fail for non-responsive nameservers
- Payment failure via x402 protocol — call blocked before execution if USDC payment is not settled

## How this service works

Machine-readable settlement service

## Output

Returns a structured object containing the MX DNS records for the queried domain, including mail exchange hostnames and their associated priority values, reflecting live DNS resolution results.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-mx-dns-records-lookup-80c9c8a7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)