err is a plugin-based XMPP chatbot designed to be easily deployable, extensible, and maintainable. It is written in Python, and is based on jabberbot and yapsy with some minor modifications to the first one. It has been tested with HipChat and Openfire, but should be compatible with any XMPP/Jabber servers. It can be set up so that a restricted list of persons have administration rights. Dynamic plugin architecture: the bot admin can install/uninstall/enable/disable plugins dynamically just by chatting with the bot. Supports MUCs (chatrooms). Can proxy and route one to one messages to MUC so it can enable simpler XMPP notifiers to be MUC compatible (such as the Jira XMPP notifier). It is easily extensible. It provides an an automatic persistence store per plugin, and a !help command that dynamically generates the documentation from the Python docstrings of the commands. Create a user for the bot on your private XMPP server or a public server like jabber.org. Optionally, you can create a MUC (also called a conference room or chatroom) in which you can interact with the bot.
Simple PHP Chat Script is an AJAX chatting system which does not require a database. It works with text files saved on the server, so it is fast and requires very few server resources. It can be included in both PHP or HTML files (in blogs, forums), but the server must run PHP. The script can easily be changed to be used in other languages, just by translating the texts in a single file. It can have one or more chat rooms. The user can add smiles in chat, and can format the text with Bold, Italic, an Underline.