Email address checker

Purpose

Check an email address without writing to it: whether it’s well written, whether its domain exists and receives email, and whether it’s a disposable, role or free-mail address, with a suggestion if the domain looks mistyped.

Requirements

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

Before you write to an address or trust one, check it here. We look at how it’s written and at its domain: whether it exists, whether it receives email and what kind of address it is. We can’t tell whether the mailbox itself exists, because we never contact its mail server, and we don’t store the address.

How to use it

1. 1

   Type or paste the email address you want to check.

2. 2

   Press “Check the address”. We check how it’s written and look up its domain in public DNS.

3. 3

   Read the result and the signals. If we suggest another domain (for example gmail.com instead of gmial.com), confirm the address with whoever gave it to you.

Synthetic example

[email protected]

Interpret the result

This isn’t a valid email address: It doesn’t have the shape of an address: the @ or the domain is missing, or it has characters an address can’t use.

The domain of this address doesn’t exist: Nobody can receive email at it. If someone gave you this address, they may have mistyped it.

The domain doesn’t receive email: It exists, but it has no mail servers or it states that it accepts no email. A message to this address won’t arrive.

The domain receives email: The address is well written and its domain has mail servers. We can’t confirm that this particular mailbox exists, only that the domain can receive email.

The address isn’t written the way an email address has to be.

The domain doesn’t exist in DNS.

The domain states that it receives no email (“null MX”).

The domain has no mail servers.

The domain has no MX records, so email goes to its own address. It works, but it’s unusual.

It’s a disposable email service: these addresses last minutes or hours and are often used to sign up without giving a real address.

It’s a role address (info@, support@, noreply@…) that belongs to a team or a service, not to one person.

It’s a free email service (Gmail, Outlook, Yahoo…). Anyone can open an account, so a bank or a company won’t usually write to you from one.

The domain looks a lot like a well-known provider’s, so the address may have been mistyped.

Limitations

The address is sent to NoCall’s server only to look up its domain in public DNS, and it isn’t stored. We never contact its mail server.

Troubleshooting

That doesn’t look like an email address. Check that it has an @ and a domain.

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

What can be known about an email address without contacting its mail server: syntax, whether the domain exists and receives email, its provider, and whether it is a disposable, role or free email address, with a suggestion for a mistyped provider domain. The mailbox itself is not checked, and the address is never stored or returned.

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/email-verify
POST https://api.nocall.io/v2/tools  {"tool":"email-verify","email":"[email protected]"}

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

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/email-verify',
    method='POST',
    data=json.dumps({'email': '[email protected]'}).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/email-verify', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer ' + apiKey,
    'Content-Type': 'application/json',
    'Idempotency-Key': requestId,
  },
  body: JSON.stringify({ email: '[email protected]' }),
});
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": "email-verify",
    "result": {
      "domain": "outlok.com",
      "domainAscii": "outlok.com",
      "status": "domain_not_found",
      "syntaxValid": true,
      "acceptsMail": false,
      "mx": {
        "count": 0,
        "provider": null,
        "implicit": false,
        "nullMx": false
      },
      "disposable": false,
      "role": false,
      "freeMail": false,
      "suggestion": "outlook.com",
      "signals": [
        "domain_not_found",
        "typo_domain"
      ],
      "attention": true
    }
  },
  "meta": {
    "requestId": "req_example",
    "unitsCharged": 1,
    "usage": {
      "periodStart": "2026-10-01",
      "unitLimit": 20,
      "unitsUsed": 3,
      "unitsRemaining": 17
    }
  }
}

• API reference ↗

Frequently asked questions

Related guides

• MX record lookup
• Is this email real?
• Check a link