Offers an explanation of the way the official client works, also includes a FAQ on connection errors and navigation tips. Apparently no longer maintained but still of interest.

Shareware Macintosh client and utilities for Hotline users.

Open source Hotline 1.2.3-compatible client for Macintosh OS X.

Open source GNU/Linux client that supports most of the latest Hotline features.

A Hotline client written for Unix/Linux-like operating systems. It employs the Gtk+ environment for the front-end and utilizes a back-end based on the HX project.

A shareware Macintosh download utility for the automated downloading of files from the Internet using popular file transfer protocols, including the Hotline protocol.

A very customizable automated Hotline client for server administration and user moderation.

A Hotline client for BeOS. A version is available for the x86 hardware platform as well as PPC.

A variant of the OpenLine client for MacOS and Windows that supports blowfish encryption. Licensed under GNU GPL.