JSON-based chat that has web and console clients, and a server
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bin Removes Sprockets dependency and adds rake test, rake assets Apr 13, 2012
.gitignore Added PID file for server Mar 22, 2010
MIT-LICENSE Added license and blog reference to the web site May 28, 2009
Rakefile Removes Sprockets dependency and adds rake test, rake assets Apr 13, 2012
jschat.gemspec Corrects date in gemspec Apr 13, 2012


JsChat is a chat system. It has an easy to learn JSON protocol, an ncurses client, a web app, and a server. You can try it right now on jschat.org.

JsChat is similar to IRC, but it’s a fundamentally simpler system.

The web app has lots of interesting features:

  • IRC-like commands: /names, /name new_name (/nick works too), /clear, /lastlog
  • It’s pretty tiny; it’s built with Sinatra and Prototype
  • Auto-linking: pasting an image displays it inline, youtube and vimeo videos will appear as well
  • Last messages are displayed on join: the last 100 messages are displayed, so you don’t feel lost when you join a room
  • Tab completion!


You can install with rubygems:

gem install jschat

Then run jschat-server and jschat-client to try out the console client locally.

To try out the web client, run jschat-web and visit http://localhost:4567.

Ruby Library Requirements

These gems are required by JsChat:

  • eventmachine
  • ncurses (for the client)
  • json


  • Run the server with ./server.rb
  • Connect a client with ./client.rb

The web app must be run alongside the server. The web app must be started in production mode:

http/jschat.rb -e production

The web app currently has no database dependencies, it’s a wrapper that links cookies to JsChat server proxies. You can run it on port 80 by configuring Rack or an Apache proxy. I have Apache set up this way on jschat.org.

Configuration Files

These are the default locations of the configuration files. You can override them with --config=PATH:

  • Client: ~/.jschat/config.json
  • Server: /etc/jschat/config.json

The web app will use the same configuration file as the server so it can find out where the server is.

The file format is JSON, like this:

{ "port": 3001 }

Server Configuration Options

  "port": integer,
  "ip": "string: IP address to bind to",
  "tmp_files": "string: path to tmp files (including PID file)"

Client Commands

  • Change name or identify: /nick name
  • Join a room: /join #room
  • Join a room (alias): /j #room

Protocol Design

The protocol is designed to be as close to executable JSON as possible, so clients and servers are simple to implement.

Look at client.rb JsChat::Protocol to see what I mean.

Hey, this is like Campfire!

I love Campfire and I didn’t intend for JsChat to compete with it. JsChat is just a fun project, it doesn’t offer Campfire’s business-friendly interface, file hosting, transcripts and Basecamp integration.


JsChat was created by Alex Young for Helicoid. A growing group of friends are helping out:

If you’d like to contribute, send alexyoung a message on GitHub.