To see Orbiter in action, visit this JavaScript chat application, which communicates seamlessly with the equivalent Flash-based chat application posted here. To see how the chat was built, view the page source.

Orbiter is already fully functional, but at this preview stage of development it is limited in the following ways:

• Does not support Microsoft Internet Explorer. IE support is the next feature scheduled for development.
• Requires Union Server 1.0 Alpha 8 preview or higher, which can be obtained here. The public testing server, tryunion.com, also supports Orbiter connections.
• No documentation. However, Orbiter's API is, in most cases, identical to Reactor's API. Furthermore, complete source code is included in the release.
• Incomplete API. Orbiter does not yet have a room manager, client manager, or account manager, nor does it have Client objects, Room objects and UserAccount objects. Instead, most communication methods are currently defined by the Orbiter class directly. In a future release, Reactor-style managers will be added to Orbiter's API, and the Orbiter class's temporary communication methods will be removed. In the interim, developers can access all Union Platform features by sending and receiving UPC messages directly via Orbiter's MessageManager.

Orbiter is currently tested and verified working in the latest version of the following web browsers: Mozilla Firefox, Google Chrome, Opera, Safari, iPhone Mobile Safari, Android Browser. Please send reports of incompatibilities to union [-a-t-] user1.net.

• Kenichi Ueno posted a proof-of-concept Objective-C "Hello World" example for creating iPhone and iPad Union clients.
• Alex W. posted AMF and JSON examples for passing complex data (e.g., objects and lists) between ActionScript clients and Union Server.

Thanks to Kenichi and Alex for making their code publicly available.

Union will be entirely free for both commercial and noncommercial projects, and will support up to 1000 simultaneous client connections.

Union Enterprise, a commercial license, will support an unlimited number of simultaneous client connections. Pricing for Union Enterprise will be announced when Union 1.0 is released.

For complete licensing details, see Union Licensing.

By releasing a free 1000-user licence, USER1 aims to make multiuser-application development significantly more accessible to innovators, businesses, and hobbyists alike. Under Union's free licence, the vast majority of realtime-multiuser applications will be able to be deployed without the need to purchase costly server software.

In order to foster community sharing, USER1 is committed to providing a free licence that supports a minimum of 1000 simultaneous client connections for all future versions of Union. We hope that this promise gives the community the confidence to develop and share custom components, server modules, applications, client SDKs, and best practices in the field of multiuser computing.

We believe that all applications should be multiuser; we hope our free Union licence helps make that belief a reality.

This release brings Union 1.0 a very large step closer to final shipping status. Only one major feature remains unimplemented (see security, permissions, and privileges). Major changes to Reactor and Union's existing APIs are now unlikely, but minor changes and expansions will continue to occur until Union 1.0 Beta 1 is released.

For more information about this release, please see the Union 1.0 Alpha 7 Release Notes.

• A chat application featuring a user list, private messaging, and account registration and login.
• A multiuser mouse pointer example, where all connected users can see each other's mouse pointers.

Both examples include fewer than 100 lines of code, demonstrating how Union's modular design helps encapsulate and organize the complexity of multiuser interface development.

Built on Adobe Flex and Reactor (Union’s ActionScript client-communications library) ReactorGUI provides Union developers with high-level multiuser-application building blocks such as a user list, a room list, an avatar pane, a chat widget, a login window, position broadcasting utilities, and a debugging panel.

ReactorGUI is a free part of Reactor, and includes all source code so developers can study, modify, and extend ReactorGUI’s component set without restriction.

Examples, an API reference, and download information for ReactorGUI are available here.

Developers can also optionally connect Union's persistence layer to an existing data source, replacing Union's built-in database with any other database or arbitrary data source. For example, a travel-booking Web site could replace Union's built-in database with an existing database of users and allow those users to login via Union's standard account API. Union applications, such as a traveller's chat or a realtime booking agent, could then be integrated directly into the Web site's existing data management system.

For sample code showing how to use Union's user-account management in ActionScript 3.0, see the new Reactor sample User Account Registration and Login.

For more information about this release, please see the Union 1.0 Alpha 6 Release Notes.