Method: channels.checkUsername

Check if a username is free and can be assigned to a channel/supergroup

Parameters:

Name	Type	Description	Required
channel	Username, chat ID, Update, Message or InputChannel	The channel/supergroup that will assigned the specified username	Optional
username	string	The username to check	Optional

Return type: Bool

Can userbots use this method: YES

Can bots use this method: NO

MadelineProto Example (now async for huge speed and parallelism!):

if (!file_exists('madeline.php')) {
    copy('https://phar.madelineproto.xyz/madeline.php', 'madeline.php');
}
include 'madeline.php';

$MadelineProto = new \danog\MadelineProto\API('session.madeline');
$MadelineProto->start();

$Bool = $MadelineProto->channels->checkUsername(channel: $InputChannel, username: 'string', );