Validate Number field in Contact Form 7

Allow numbers only in ‘number’ field in Contact Form 7 plugin, add the following code in your functions.php

/*
Validate Numbers in Contact Form 7
This is for 10 digit numbers
*/

function is_number( $result, $tag ) {
$type = $tag['type'];
$name = $tag['name'];

if ($name == 'request-phone') {
$stripped = preg_replace( '/D/', '', $_POST[$name] );
$_POST[$name] = $stripped;
if( strlen( $_POST[$name] ) != 10 ) { // Number string must equal this
$result['valid'] = false;
$result['reason'][$name] = $_POST[$name] = 'Enter 10 digit phone number.';
}
}
return $result;
}

add_filter( 'wpcf7_validate_text', 'is_number', 10, 2 );
add_filter( 'wpcf7_validate_text*', 'is_number', 10, 2 );

How to call it in the admin section

[number request-phone]

Replace “request-phone” with your field name.