SwiFTP is described as 'open-source FTP server that allows you to connect to your phone over wifi or cellular/3g to upload and download files. Any FTP client can be used' and is an app in the File Sharing category. There are four alternatives to SwiFTP for a variety of platforms, including Windows, Linux, Mac, Android and BSD. The best alternative is OpenSSH, which is both free and Open Source. Other great apps like SwiFTP are FreeFTPd (Free), SSHDroid (Free) and Serv-U Managed File Transfer Server (Paid).
OpenSSH is a free version of the SSH connectivity tools that technical users rely on. OpenSSH encrypts all traffic (including passwords) to effectively eliminate eavesdropping, connection hijacking, and other attacks.
freeFTPd is a FTP/FTPS/SFTP server that enables user to access remote files over TCP/IP network such as Internet. Unlike FTP, FTPS and SFTP protocols provide security and strong encryption of data - great for insecure network.
SSHDroid is a SSH server implementation for Android. This application will let you to connect to your device from a PC and execute commands (like "terminal" and "adb shell") or edit files (through SFTP, WinSCP, Cyberduck, etc...).