The goal of XULRunner is to provide a solution for deploying XUL applications (primarily Firefox and Thunderbird), as well as providing an embedding mechanism. The following features are either already implemented or planned:

Gecko Features

• XPCOM
• Networking
• Gecko rendering engine
• DOM editing and transaction support (no UI)
• Cryptography
• XBL (XBL2 planned)
• XUL
• SVG
• XSLT
• XML Extras (XMLHttpRequest, DOMParser, etc.)
• Web Services (SOAP)
• Auto-update support (not yet complete)
• Type ahead find toolbar
• History implementation (the places implementation in the 1.9 cycle)
• Accessibility support
• IPC services for communication between gecko-based apps (not yet complete)
• Storage/sqlite interfaces

User Interface Features

The following user interface is supplied by XULRunner, and may be overridden by embedders under certain circumstances:

• APIs and user interface for installing, uninstalling, and upgrading XUL applications. See the wikimo:XUL:Installation Story.
• Extension Manager
• File picker (uses native OS filepicker as appropriate)
• Find toolbar
• Helper app dialog/UI
• Security UI (maintenance of SSL keychains, etc)

Embedding APIs

The following embedding APIs are provided by XULRunner:

• Cross-platform embedding (XRE_InitEmbedding)
• JavaXPCOM embedding
• gtkmozembed (Linux only)
• ActiveX control (Windows only) (not yet complete) Obsolete since Gecko 7.0
• NSView-based-widget (Mac OS X only) (not yet complete)

The "Maybe" List

The following features have been discussed and may be included if developer time permits and code size is controlled:

• LDAP support
• Spellchecking support (with or without dictionaries provided) see bug 285977
• Core support for profile roaming (with application-specific extensibility)
• PyXPCOM embedding (not yet complete) - but it does work, if you compile a custom build that includes the PyXPCOM bindings and there is a working python available. ActiveState uses PyXPCOM in their products.

What's out

XULRunner will not supply:

• Bookmarks or History UI (must be managed by the application/embedder)
• XForms (XForms will be available as an extension)