Mail Server Lookup

Look up a domain's MX, A, AAAA, NS, TXT and SOA records, identify its email provider, and show its SPF and DMARC records.

Pay by wallet (x402) mx-lookup

Example

Input

{
  "domain": "google.com"
}

Answer

{
  "soa": {
    "serial": 879543655,
    "primary_ns": "ns1.google.com",
    "admin_email": "dns-admin.google.com"
  },
  "domain": "google.com",
  "has_mx": true,
  "has_spf": true,
  "has_ipv6": true,
  "a_records": [
    "172.253.115.138",
    "172.253.115.102",
    "172.253.115.100",
    "172.253.115.113",
    "172.253.115.139",
    "172.253.115.101"
  ],
  "has_dmarc": false,
  "mx_records": [
    {
      "exchange": "smtp.google.com",
      "priority": 10
    }
  ],
  "spf_record": "v=spf1 include:_spf.google.com ~all",
  "nameservers": [
    "ns3.google.com",
    "ns2.google.com",
    "ns1.google.com",
    "ns4.google.com"
  ],
  "aaaa_records": [
    "2607:f8b0:4004:c1f::71",
    "2607:f8b0:4004:c1f::8a",
    "2607:f8b0:4004:c1f::65",
    "2607:f8b0:4004:c1f::66"
  ],
  "dmarc_record": null,
  "email_provider": "Google Workspace"
}

Inputs

Field	Type	Required	What it is
`domain`	string	Yes	—

Output fields

How reliably each field appears in a successful answer.

Field	Type	Appears
`domain`	string	Always (present in every successful answer)
`has_spf`	boolean	Always (present in every successful answer)
`has_dmarc`	boolean	Always (present in every successful answer)
`mx_records`	array	Always (present in every successful answer)
`email_provider`	string	Always (present in every successful answer)

How to call it

The same tool through each route. MCP clients reach it through Strale’s server at https://api.strale.io/mcp; the call below is what the agent sends.

# Needs an API key. max_price_cents caps what this call may cost.
curl -X POST https://api.strale.io/v1/do \
  -H "Authorization: Bearer $STRALE_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
    "capability_slug": "mx-lookup",
    "inputs": {
      "domain": "google.com"
    },
    "max_price_cents": 2
  }'

{
  "tool": "strale_execute",
  "arguments": {
    "slug": "mx-lookup",
    "inputs": {
      "domain": "google.com"
    },
    "max_price_cents": 2
  }
}

import { Strale } from "straleio";

const strale = new Strale({ apiKey: process.env.STRALE_API_KEY! });
const result = await strale.do({
  capability_slug: "mx-lookup",
  inputs: {
    "domain": "google.com"
  },
  max_price_cents: 2,
});

import os
from straleio import Strale, DoRequest

strale = Strale(api_key=os.environ["STRALE_API_KEY"])
result = strale.do(DoRequest(
    capability_slug="mx-lookup",
    inputs={
        "domain": "google.com",
    },
    max_price_cents=2,
))

# No account. The first request answers 402 with the price in USDC;
# an x402 client pays it from your wallet and repeats the request.
curl -i 'https://api.strale.io/x402/v2/mx-lookup?domain=google.com'

Limitations

MX records do not confirm server reachability
Returns MX records from DNS — cannot verify whether the mail server is actually accepting connections
What to do instead: Combine with port-check on port 25 of the returned MX hosts to verify mail server reachability