Hotline is a modern Swift client for a 1997 chat network

A client for a network that never fully died

Hotline was released in 1997 for Mac OS as a suite of three free applications that let people join or host online communities directly from their Macs, with no subscriptions and no ads. Connected to a Hotline server, you could chat with other users like IRC, message them privately like AIM, read or write threaded news like a forum, post to a message board like a BBS, and browse, upload or download files like FTP, and someone operating a server had full control over all of it. Hotline also included Trackers, which tracked servers so people could find them, and anyone could run a Tracker. The reason this project exists is that communities are still operating more than 25 years later, even though the company that made the original software is gone and that software survives only in retro Mac archives. The project description is simply that it is an attempt to create a modern open source version of Hotline for modern Apple systems. The topics on the repository, chat, chat-app, chat-application, hotline, hotline-client, say the same thing more plainly.

The feature table shows how uneven the port is

The status table in the README is the most informative part of the repository, and it is not uniformly green. The macOS column carries almost everything. Trackers listing, multiple trackers, connecting to servers and to multiple servers, server accounts, server bookmarks, changing name and icon, privacy settings, autoresponse, public chat, public chat search and public chat persistence, private messages, the user list, user icons, user administration, news reading and posting, message board reading and posting, file browsing, downloading, uploading, info and search, and folder downloading and uploading are all marked for macOS. The iOS column is much shorter. Trackers listing, display of server agreement and banner, public chat, the user list, user icons, news reading and posting, message board reading and posting, and file browsing are marked, but file downloading, file uploading, private messages and multiple trackers are not. The iPadOS and visionOS columns are entirely empty, which matches the README's note that iOS, iPadOS and visionOS are still in the works. Two rows are unchecked everywhere, file management and custom icon sets. Any plan that depends on uploading files from an iPhone is not supported by the current state of the code.

It ships no server, and it points you at Mobius

This project does not include server software. That is stated plainly in the README, and the client is for connecting to and participating on Hotline servers. If you want to host your own server, the project points at a third party effort, the Mobius project hosted under the jhalter account, described as very capable and free. That boundary is the single most important fact for anyone evaluating the project, because a Hotline network needs both ends. The client is the part being rebuilt here, and the server side is delegated to existing software that predates the remake. The goals section confirms the scope, listing building a Hotline client for modern Apple systems, bringing a Hotline client to iOS, iPadOS and macOS using one codebase, documenting the Hotline protocol, and resurrecting the Hotline brand, which the author notes has been expunged from trademark databases for over a decade. The project also sets a technical goal that matters for reuse: keeping the HotlineProtocol, HotlineClient, HotlineTrackerClient and HotlineFileClient Swift code reusable so people can use it in other Swift Hotline projects.

Four Swift modules and a research directory

The repository layout matches those goals. At the top level there is Hotline.xcodeproj/, the Hotline/ directory holding the application and the library code, a HotlineTests/ directory for tests, a Research/ directory, a LICENSE.md, the README and a .github/ directory. The primary language is Swift, and the badges at the bottom of the README indicate Swift 5.0 and an MIT licence. The four named components in the goals map onto the idea of a layered protocol client. HotlineProtocol is the wire format, and the documentation goal is to describe that protocol. HotlineClient is the connection to a server, HotlineTrackerClient handles the tracker listing that lets people discover servers, and HotlineFileClient covers the file transfer portion, which is the feature that the platform support table shows is macOS only. The Research/ directory is the clearest hint about how this is being built, since it is the natural place for notes on the original protocol, and the project lists documenting the Hotline protocol as an explicit goal rather than an afterthought.

Only the newest Apple platforms are supported

The platform requirement is strict. The README states that macOS 26 (Tahoe) and up is required, and the stated intention is to support the last two major OS releases from Apple, so that people have time to move to the latest major release while the project can also use the latest APIs. That is a deliberate policy rather than an accident of neglect, and it has a real cost for anyone running the software. A machine on an older macOS cannot run the client at all, so participating in the community becomes a reason to upgrade. There is also a visible inconsistency inside the README itself. The requirement line says macOS 26 (Tahoe) and up, while the badge near the bottom of the file still reads macOS 15+. Two different floors are stated in the same document, and the prose one is the stricter and more recent. If you are checking compatibility before pulling the build, trust the requirement line and the release notes rather than the badge.

Where this client stops, and what to check first

The limits are structural. There is no server in this repository, so adopting the client does not give you a Hotline network. The iOS build is a partial implementation, missing private messages, file transfer, multiple trackers and several server management features, and the iPadOS and visionOS builds are not yet there. The client also targets a 1997 protocol, which means the security posture is that of the original design rather than of a modern messenger, and the README does not document encryption, authentication hardening or how credentials are stored on the platform. The project is a beta in the strictest sense, with releases named 1.0beta29, 1.0beta28 and 1.0beta27, and the last push was on 2026-10-12 with the most recent release on 2026-10-05. Anyone picking this up should check the release binaries for the platform in front of them, read the README requirement for the OS floor rather than the badge, and decide early whether they need the file transfer features, since those decide whether the app is usable for their purpose or only a chat client.

Editorial conclusion

Adopt Hotline if you want to take part in the surviving Hotline community on modern Apple hardware, or if you want a documented, reusable Swift implementation of the Hotline protocol to build on. Do not expect a server from this repository, since the project states it ships no server software and points to the Mobius project for that. Verify first that you are on macOS 26 or later, since the README requires it even though one badge in the file still reads macOS 15+, and confirm which of the protocol clients you need are already usable given the feature table marks several of them as macOS only.

Frequently asked questions

Official sources

1. Issues
2. License: MIT
3. mierau/hotline on GitHub
4. README
5. Releases