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Checks a telephone number for validity.

The service returns a code indicating the status of the telephone number. This code can be one of the following values:

  • Valid - the telephone number is valid
  • Invalid - the telephone number is invalid
  • TemporaryInvalid - the telephone number is invalid, but may become valid shortly
  • Ambiguous - we got a response from the telephone network that can indicate either a valid or invalid number
  • NumberChanged - the telephone number is invalid, but calling it will give you a recording telling you a new number
  • Unknown - we could not determine the validity of the number
  • Error - an error occurred communicating with the telephone network
  • TimedOut - we did not get a response from the telephone network in a timely manner

In normal circumstances you should only receive the first four status codes. If you receive one of the final three status codes, we will investigate the cause and attempt to ensure it does not happen again, and you will not be charged for the query.

This service is not appropriate if you require an absolute indication that a telephone number is valid for a particular individual. In those circumstances, you should consider the use of a telephone number capture service.


A comma-separated list of prefixes in standard international format that the number must start with to be treated as valid. For example, use "+441,+442" to allow only standard UK landline numbers.

A comma-separated list of prefixes in standard international format that will cause the number to be treated as invalid. For example, use "+4470,+449" to block any personal non-geographic or premium rate numbers.

View all Live Number Testing (part of the of the phone validation suite) methods

Code Samples

<!-- Import the Integr8 Ajax API -->
<!-- NOTE: Get your own API key to use in the following script tag from: -->
<!-- http://www.data-8.co.uk/integr8/Admin/Ajax.aspx -->
<script src="https://webservices.data-8.co.uk/Javascript/Loader.ashx?key=your-api-key" type="text/javascript">

<script type="text/javascript">

function loadIntegr8() {
  // Load the TelephoneLineValidation Integr8 service

function IsValid(number) {
  /// <param name="number">string</param>
  var telephonelinevalidation = new data8.telephonelinevalidation();

function showIsValidResult(result) {
  // Check that the call succeeded, and show the error message if there was a problem.
  if (!result.Status.Success) {
    alert('Error: ' + result.Status.ErrorMessage);
  else {
    // TODO: Process method results here.
    // Results can be extracted from the following fields:
    // result.Result
    //   Indicates if the telephone number is found to be valid.