Do you need to make it possible for others to connect to your application using the SFTP protocol? Use one of the following libraries.

Alternatively, if you only need a ready-made stand-alone server, see the list of SFTP servers.

Disclaimer: This site was created by developers of one of components listed below.

.NET components

NameNote
Rebex File ServerSFTP and SSH server library from creators of this site.
ComponentPro SFTP ServerA .net library based on stolen code. ComponentPro is currently being sued for copyright infringement.
Nuane SFTP Server LiteThis library evolved into Rebex File Server.
Secure BlackboxUsed to be called Eldos Secure Blackbox. Now is owned by the /n software.

Java components

NameNote
Apache MINANetwork application framework with SFTP/SSH support.
JAdaptive Java SSH Server APICommercial Java SSH implementation
Maverick Synergy Java SSH APIOpensource SSH API
SecureBlackBoxUsed to be called Eldos Secure Blackbox. Now is owned by the /n software.