<?php
    //include the library 'phpseclib0.2.1a' downloded and extracted to the same directory level of this script
    set_include_path(get_include_path() . PATH_SEPARATOR . 'phpseclib0.2.1a');
    require_once('Net/SFTP.php');

    //connection parameters
    $host = 'host_url';
    $port = 'host_port_number';
    $username = 'host_user_name';
    $password = 'host_password';

    //Connect to SFTP host
    $sftp = new Net_SFTP($host, $port);

    if ( $sftp->login($username, $password) ) {
        //directory path to source and destination
        $localDirectory = '/local_directory_name/';
        $remoteDirectory = '/remote_upload_directory_name/';

        //save all the filenames in the following array
        $filesToUpload = array();

        //Open the local directory and store all file names in $filesToUpload array
        if ( $handle = opendir($localDirectory) ) {

            //loop the local source directory
            while ( false !== ($file = readdir($handle)) ) {

                if ( $file != '.' && $file != '..' ) {
                    $filesToUpload[] = $file;
                }

            }
       
            closedir($handle);
        }

        //if source directory has any file to upload then upload all files to remote server
        if ( ! empty($filesToUpload) ) {
            //upload all the files to the remote server

            foreach ( $filesToUpload as $file ) {
                //Upload the local file to the remote server
                $success = $sftp->put(
                                      $remoteDirectory . $file,
                                      $localDirectory . $file,
                                      NET_SFTP_LOCAL_FILE
                                      );

                if ( $success ) {
                    echo '<br>uploaded ' . $file . '<br>';
                }    
            }
        } 
    } else {
        exit('Login Failed');
    }
?>

<?php
    //include the library 'phpseclib0.2.1a' downloded and extracted to the same directory level of this script
    set_include_path(get_include_path() . PATH_SEPARATOR . 'phpseclib0.2.1a');
    require_once('Net/SFTP.php');

    //connection parameters
    $host = 'host_url';
    $port = 'host_port_number';
    $username = 'host_user_name';
    $password = 'host_password';

    //Connect to SFTP host
    $sftp = new Net_SFTP($host, $port);

    if ( $sftp->login($username, $password) ) {
                //create file on remote server directory and with some text in it
                $success = $sftp->put(
                                      '/remote_upload_directory_name/file_name.text',
                                      'hello, world!'
                                      );
    } else {
        exit('Login Failed');
    }
?>

• phpseclib has pretty much zero server requirements. So long as the server supports PHP it’ll work.
• ibssh2, in contrast, has to be installed on the server for it to work and a lot of servers don’t have it installed.
  IF it is installed you’re not going to need to include any additional files (whereas with phpseclib you will have to include them but that’s a big IF.