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SFTP Component for .NET - SSH File Transfer Client Library

Easily add comprehensive SSH Secure File Transfer capabilities to your .NET applications

Ultimate SFTP is a 100%-managed .NET class library that adds powerful SSH Secure File Transfer (SFTP) capabilities to your applications. It is fast, reliable, and feature-rich. Ultimate SFTP makes it possible to upload, download, create, delete, and check files and directories with a few lines of code.

If you need the Xamarin Android, iOS and .NET CF version, visit Ultimate SFTP Library for Mobile for more details.

Ultimate SFTP for .NET is also included in

Why Choose Ultimate SFTP?

Intuitive API

Easily connect, authenticate, upload/download a single file or multiple files and folders, and disconnect. It also supports many advanced SFTP operations with a single line of code, e.g. multi-thread files transfer, folders synchronization, server to server multiple files transfer, etc.

// Create a new instance of the Sftp class.
using (Sftp client = new Sftp())
    // Connect to the server.

    // Authenticate the user
    client.Authenticate(userName, password);

    // Upload the local file.
    client.UploadFile(@"c:\folder\data.dat", "/file.dat");

    // Download "*.dat" and "*.txt" files.
    client.DownloadFiles("/data/*.dat;*.txt", @"c:\data");
With Ultimate SFTP you can authenticate using a username and password pair, username, password, and private key, or an X509 certificate.

Fast, reliable, and minimized memory footprint

It is highly optimized for socket connections and File Transfer Protocol and is especially helpful in SFTP applications where performance is key such as when transferring a large number of files and/or large files.

Manage files and directories with ease

All the common single file operations and directory operations, including upload/download, multi-part download, rename/move, delete, check existing, get file info, set/get file time, and get file checksum can be done with a single line of code.

Upload/download, delete, or move multiple files at once. Flatten/merge multiple files and directories. Synchronize files and folders. All the multi-file operations can be done with only one line of code. They also accept name and path masks to filter the files and directories to process. Rich events are used to monitor the transfer.


The library enables you to build applications with many security features including enabling only the Federal Information Processing Standards (FIPS) approved encryptions, verifying server key, generating private/public key pairs, and more.

Auto-reconnect and Auto-resume

If an operation or file transfer is interrupted due to a broken connection, the component automatically determines whether it should reconnect to the server if the auto-reconnect feature is enabled. When the connection is reestablished, the component will resume the interrupted transfer. As a benefit your application can still transfer files completely even if the connection to the server is intermittently broken without requiring additional code to handle the errors.

Fully Documented, well written sample projects

The component API is fully documented, making it easy to start writing code in any .NET languages like C#, VB.NET, J#, C++, or F# to connect and transfer files to your SFTP servers. Our online documentation can also be integrated to your Visual Studio IDE and is shown instantly when you press F1.

You will see that our sample projects are well written with detailed comments to help you start using our library easily.

Platforms and Standards

In addition to supporting .NET Framework, the component also lets you integrate its powerful API to your Mono applications, making it possible to create cross-platform projects.

The following platforms are supported:

  • .NET Framework: 2.0, 3.5, 4.0, 4.5, 4.5.1
  • Mono: 2.1, 3.+ on MAC OS X and Linux


  • SFTP (RFC 4250, 4251, 4252, 4253, 4254, 4256, 4419, 4462)
  • SFTP v3 and v4
For Xamarin Android, iOS and .NET Compact Framework platforms, visit our Ultimate SFTP for Mobile page.

Many more well-tested features

Ultimate SFTP has been around for nearly 8 years and thousands of .NET developers have been using it. It is tested thoroughly before any release. You will be confident when using it. Here are some more features:

  • Unified API for FTP, SFTP, ZIP, and Disk File System
  • Transfer Queue
  • Transfer throttle
  • FIPS 140-2 compliant mode
  • Powershell, SSIS, SQL CLR support
  • ZLib compression
For more details, see the feature page.


With their quick response, now I can easily solve my issue by adding a few lines of code to my application. And EXCELLENCE is the word best describes your products.
David Callaghan - Senior Software Developer SIEMENS
We use Ultimate SFTP and FTP components in all of our web and windows applications. We find the Ultimate libraries full of great flexible and easy-to-use features that make the File Transfer programming easier than ever before. In addition, Their support is very professional.
David Clark - Software Developer EmailDuty