FileCatalyst Direct Client Applications

FileCatalyst Direct includes a range of client options to choose from in order to accommodate different purposes within your organization. By using these for file transfer with a FileCatalyst Server, uploads and downloads are extremely reliable and fast—up to hundreds of times faster than FTP.

Choose HotFolder for automation, TransferAgent or applets for web integration, Express Client for basic on-demand transfers, the mobile uploader for transfers on-the-go, CLI (Command-line Interface) for scripting or non-GUI environments, and an SDK for building custom FileCatalyst clients.

Shared Client Features

Although each client offers a different experience and some different features, they share core features of the FileCatalyst protocol (click to expand):

Fast File Transfer

FileCatalyst Acceleration is a UDP-based protocol that is immune to packet loss and latency, resulting in transfers up to hundreds of times faster than FTP. The protocol also provides a number of transfer management features, while being more secure and reliable than TCP-based protocols like FTP or HTTP. A longer description is available in the Fast File Transfer section of the FileCatalyst Server page.


With security options enabled on the FileCatalyst Server, clients authenticate over SSL, and data transfer may be encrypted by AES. Clients may be required to authenticate using the organization's Active Directory / LDAP / MySQL server, adding an extra layer of security.


FileCatalyst Clients provide reliability in terms of:

  • On-the-fly or per-file verification using MD5 checksums
  • Configurable retry and resume options to pick up transfers after losing network connectivity.
  • User-definable socket timeouts to accommodate extremely poor network conditions.
  • Re-sending dropped packets, but only the packets that are missing.
  • Server-driven alerts to notify stakeholders of successful, failed, or canceled transfers, keeping them in the loop in the rare event that manual intervention is required.

Delta Transfers

Delta transfer is an rsync-like function that allows you to send only the difference between revisions of the same file. Imagine a 4MB change within an 8GB disc image. Calculating and then sending that 4MB difference is incredibly fast compared to re-sending the entire file. (Not available in the Express App)


FileCatalyst uses Gzip to compress data for additional savings in transfer time. Since not all files are compressible, FileCatalyst will ignore files on an customizable list of compressed file types. Compression is either on-the-fly (at the block level) or per file.

The Gzip functionality also allows the creation of non-compressed single archives, which greatly reduces the amount of "housekeeping" the client machine must perform when sending very large numbers of small files. With no set-up and tear-down for individual small files, the link is used for nonstop data transfer.

Progressive Transfers

Transfers using the “progressive” functionality will begin before a file is complete. This is useful for things like rendering video or zipping a file; the transfer can get underway while the render or zip process is still working. By using the progressive feature, large files arrive as early as possible at the destination.

HTTP Fallback

When UDP-based acceleration fails due to extreme security measures (firewall or NAT blocking UDP traffic wholesale, for example), it is still critical for files to get through. FileCatalyst Clients that are configured for fallback will then attempt multi-stream FTP, then single-stream FTP, and finally fall back to HTTP, which any organization that allows internet access will allow.


FileCatalyst HotFolder is a desktop application that is installed on the end-user's machine and allows the creation of scheduled, automatic tasks. Features specific to HotFolder include:

  • Automated Transfers: Set transfer tasks which execute at a set interval. When the task executes, files are sent or received based on your custom settings.
  • Bandwidth Scheduling: HotFolder allows you to set your bandwidth usage around a schedule; for example, you might throttle workday usage.
  • Filtering: Break jobs into subtasks with filters. Set inclusive or exclusive filters according to type, size or matched string. Need something more powerful? Switch to regular expressions (regex).
  • Folder Replication: Create synchronization tasks for mirroring or replicating large directories over WAN. These tasks are ideal for creating a solution for offsite disaster recovery backups.


FileCatalyst TransferAgent offers a new way to leverage FileCatalyst technology from within a browser, allowing files to be sent at speeds up to 10Gbps securely and reliably. Like all other FileCatalyst products, TransferAgent is able to overcome poor network conditions to ensure files arrive at their destination.

TransferAgent combines a desktop application (the "agent" itself) with an HTML5 interface that allows browsing local or remote file listings, selecting files for transfer, and initiating transfer without the use of browser plugins. Additionally, the flexible interface allows organizations to set up a button for downloading preselected files. Once a transfer is under way, progress updates are published to the web browser; however, the browser window or tab can be closed at any time and the transfer will continue.

There are many integration options for TransferAgent, below is an example of upload and download. All files uploaded to the demo server, are automatically deleted after 15 minutes.

  • Upload Example: Local directory listing and an upload queue (files are automatically deleted after 15 minutes)
  • Download Example: Remote directory listing and a download queue
  • Java Applets

    Our applets allow you to embed FileCatalyst technology into any web page. The biggest benefit is that the end-user needs only their web browser with the Java Plugin enabled in order to transfer files with full acceleration. Java Applets are supported by almost all Browser/Platform combinations and can be centrally deployed and upgraded. The applets can be used as the basis for a new or existing file transfer portal. They also appear in our FileCatalyst Webmail and FileCatalyst Workflow applications as fully integrated web-based file transfer components in those solution.

    There are many integration options for the applets, including JSP, PHP, ASP, Ruby and many other server side combinations. The applets also include integration/programming examples for most popular web technologies.

    Below is a list of our most popular file transfer applets that include FileCatalyst acceleration technology:

    • 2-Way Applet: resembles an FTP client, with remote and local listings and options
    • Upload Applet: used when only uploading is required, or when upload events trigger the next step of a web application
    • Download Applet: used for download-only transactions, or when download events trigger a subsequent step in a web application
    • JavaScript API: build your own web based components for transferring files. Add accelerated file transfer functionality to your existing Flex, Flash or Silverlight web components.
    The following blog article, compares Java Applets to all other web based file transfers methods: Comparison of web based file transfer methodologies.

    Express Client

    Some users prefer working through a desktop application, and yet don't need the full feature set of FileCatalyst HotFolder. Others are moving to a FileCatalyst solution from basic FTP, and have used desktop FTP clients in the past. For either of these scenarios, the Express Client provides a straightforward two-pane transfer application, closely resembling traditional FTP clients. Drag and drop files between the “local” file system in the left pane, and the “remote” FileCatalyst account in the right pane. Account settings and credentials can be saved for future sessions.

    FileCatalyst for Mobile

    FileCatalyst Upload—our mobile client—is a streamlined upload application developed for iOS and Android devices. Now any user “in the field” can easily send media files to FileCatalyst and FTP servers.

    Our Mobile SDK offers the option to develop custom applications for iOS using Objective-C, or for Android using the Java API compiled for the Dalvik environment.

    Download for Android: Google Play
    Download for iOS: Apple App Store

    Command Line Interface

    The CLI can be triggered using scripts or by applications developed in languages other than Java. If your existing process already uses command-line FTP in a script or application, switching it out for command-line FileCatalyst is a simple upgrade which yields enormous benefits. Naturally, the CLI can also be used by itself as a client within a console environment.

    FileCatalyst SDK

    The FileCatalyst SDK is available in native Java, C++ and JavaScript, or in a wrapper for C#/.NET. In addition, a SOAP API in standalone, servlet container, or J2EE server environments enable building applications on a web services interface. The CLI (described above) provides yet another way to embed FileCatalyst into your applications.

    The SDK includes both Client and Server APIs. Use the Client API to build an accelerated file transfer application or component. Use the Server API to build an interface for controlling (ie. not “creating”) a FileCatalyst Server.

    Learn More →

    HTTP Tunneling

    FileCatalyst clients may connect through an HTTP Tunnel if enabled on the FileCatalyst Server. This allows transfers to succeed even if UDP, FTP, or standard HTTP Upload are blocked by the firewall.

    Other file transfer solutions simply send data as HTTP over their data channel or port 80. This will work with firewalls that stop UDP and FTP traffic wholesale, but will not overcome firewalls that also block large HTTP transactions.

    FileCatalyst sends files using HTTP POST in relatively small pieces. This has two benefits: first, there is no file size restriction; second, firewalls will interpret transfers as normal internet activity. Even if the firewall is configured to shut down typical HTTP file transfers, FileCatalyst-based transfers will get through.