Phone number validator and formatter

Purpose

Check whether a phone number is valid, whether it is a mobile, landline, freephone or premium number, and see it in E.164, national and international format.

Requirements

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

Paste any phone number to check whether it is valid, what type of number it is and how to write it in E.164, national and international format.

How to use it

1. 1

   Open tool

2. 2

   Paste any phone number to check whether it is valid, what type of number it is and how to write it in E.164, national and international format.

3. 3

   Check

4. 4

   Read the available fields alongside their limitations. An empty result does not prove safety or identify a person.

Synthetic example

+44 1632 960123

Interpret the result

Read the available fields alongside their limitations. An empty result does not prove safety or identify a person.

It is the international standard for writing a number: a plus sign, the country calling code and the national number, with no spaces or leading zero. Apps and phone systems use it to store numbers.

No. Valid means it belongs to a range that is allocated in the numbering plan. Whether that exact number is connected today is something only the operator knows.

The type belongs to the range, not to the line, and it stays the same when the number moves to another operator. Internet telephony numbers can look like landlines.

Limitations

Indicative information from published numbering plans. It describes the type of number, never the person or company behind it.

Troubleshooting

If the input is invalid, check its format and country. Retry connection errors; respect the waiting period when a limit is reached.

Enter a valid phone number or prefix.

We couldn’t check it right now. Please try again in a moment.

Use with the API

Numbering-plan validity, possibility, type, country, calling code and E.164. Any phone-like input is a successful result: valid=false is returned, never an error.

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/number-validator
POST https://api.nocall.io/v2/tools  {"tool":"number-validator","phone":"+12025550123","country":"US"}

REQUEST_ID="$(uuidgen)" && [ -n "$REQUEST_ID" ] &&
curl --request POST 'https://api.nocall.io/v2/number-validator' \
  --header "Authorization: Bearer $NOCALL_API_KEY" \
  --header 'Content-Type: application/json' \
  --header "Idempotency-Key: $REQUEST_ID" \
  --data '{"phone":"+12025550123","country":"US"}'

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/number-validator',
    method='POST',
    data=json.dumps({'phone': '+12025550123', 'country': 'US'}).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/number-validator', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer ' + apiKey,
    'Content-Type': 'application/json',
    'Idempotency-Key': requestId,
  },
  body: JSON.stringify({ phone: '+12025550123', country: 'US' }),
});
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": "number-validator",
    "result": {
      "valid": true,
      "possible": true,
      "country": "US",
      "callingCode": "1",
      "type": "fixed_line_or_mobile",
      "e164": "+12025550123"
    }
  },
  "meta": {
    "requestId": "req_example",
    "unitsCharged": 1,
    "usage": {
      "periodStart": "2026-10-01",
      "unitLimit": 20,
      "unitsUsed": 3,
      "unitsRemaining": 17
    }
  }
}

• API reference ↗

Frequently asked questions

Related guides

• How much does it cost to call back?
• Who is calling me?