MX record lookup

Purpose

Find out whether a domain receives email, which mail servers it uses (its MX records, in priority order) and which provider runs them: Google, Microsoft 365, Zoho, Proton and others.

Requirements

Anyone can read these guides, no account needed. Some tools require Pro, as indicated in each guide.

Every domain that receives email lists its mail servers in DNS, in its MX records. Type a domain, an email address or a link and we’ll tell you whether it can receive email, which servers handle it and who runs them. We only read public DNS.

How to use it

1. 1

   Type a domain such as example.com, or paste an email address or a link: we only use its domain.

2. 2

   Press “Look up MX”. We read the domain’s MX records in public DNS and check that each server has an address.

3. 3

   Read the result: whether the domain receives email, its servers in the order they’re tried and the provider behind them.

Synthetic example

example.com

Interpret the result

This domain receives email: It lists its mail servers in DNS, so a message sent to an address at this domain has somewhere to go.

It receives email, but something is wrong: It lists mail servers, but at least one of them is misconfigured, so some messages may be delayed or lost.

This domain doesn’t receive email: It lists no mail servers, or it states that it accepts no email. A message sent to an address at this domain won’t arrive.

This domain doesn’t exist: It isn’t registered or it has no DNS. Nobody can receive email at it, so be wary of a message that claims to come from it.

Servers with a lower priority number are tried first; the others are backups.

Limitations

Troubleshooting

That doesn’t look like a public domain. Try something like example.com.

DNS didn’t answer in time. Try again in a few seconds.

You’ve run a lot of checks in a row. Wait a minute and try again.

Use with the API

Whether a domain receives email: its MX servers in priority order, whether each one has an address, a null or implicit MX, and the provider that runs them (google, microsoft, zoho, proton, amazon_ses and others). Accepts a domain, an email address or a link. Public DNS only; nothing is stored.

Send the JSON body to the tool's own route, or to POST /v2/tools with the tool field added. Both routes return the same result.

POST https://api.nocall.io/v2/mx-lookup
POST https://api.nocall.io/v2/tools  {"tool":"mx-lookup","domain":"example.com"}

REQUEST_ID="$(uuidgen)" && [ -n "$REQUEST_ID" ] &&
curl --request POST 'https://api.nocall.io/v2/mx-lookup' \
  --header "Authorization: Bearer $NOCALL_API_KEY" \
  --header 'Content-Type: application/json' \
  --header "Idempotency-Key: $REQUEST_ID" \
  --data '{"domain":"example.com"}'

import json
import os
import urllib.request
import uuid

api_key = os.environ.get('NOCALL_API_KEY')
if not api_key:
    raise SystemExit('Set NOCALL_API_KEY')

request = urllib.request.Request(
    'https://api.nocall.io/v2/mx-lookup',
    method='POST',
    data=json.dumps({'domain': 'example.com'}).encode(),
    headers={
        'Authorization': 'Bearer ' + api_key,
        'Content-Type': 'application/json',
        'Idempotency-Key': str(uuid.uuid4()),
    },
)
with urllib.request.urlopen(request, timeout=30) as response:
    result = json.load(response)
print(result['data']['result'], result['meta']['unitsCharged'])

import { randomUUID } from 'node:crypto';

const requestId = randomUUID();
const apiKey = process.env.NOCALL_API_KEY;
if (!apiKey) throw new Error('Set NOCALL_API_KEY');

const response = await fetch('https://api.nocall.io/v2/mx-lookup', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer ' + apiKey,
    'Content-Type': 'application/json',
    'Idempotency-Key': requestId,
  },
  body: JSON.stringify({ domain: 'example.com' }),
});
const result = await response.json();
if (!response.ok) throw new Error(result.error?.code ?? 'request_failed');
console.log(result.data.result, result.meta.unitsCharged);

{
  "data": {
    "tool": "mx-lookup",
    "result": {
      "domain": "example.com",
      "domainAscii": "example.com",
      "found": true,
      "records": [
        {
          "priority": 1,
          "host": "aspmx.l.google.com"
        },
        {
          "priority": 5,
          "host": "alt1.aspmx.l.google.com"
        }
      ],
      "nullMx": false,
      "implicitMx": false,
      "acceptsMail": true,
      "provider": "google",
      "signals": [],
      "attention": false
    }
  },
  "meta": {
    "requestId": "req_example",
    "unitsCharged": 1,
    "usage": {
      "periodStart": "2026-10-01",
      "unitLimit": 20,
      "unitsUsed": 3,
      "unitsRemaining": 17
    }
  }
}

• API reference ↗

Frequently asked questions

Related guides

• SPF record checker
• DMARC checker
• Email address checker