Getting started with Opera (.oex) Extensions

This documentation relates to Opera's now deprecated .oex Extension API framework for Opera versions <= 12.15 and also provided by our OEX2NEX shim library.

For the latest Opera Extensions API documentation for Opera versions > 12.15 please consult the latest Opera Extensions API documentation online.

• Saying hello world to Opera extensions
• What's in an Opera extension?
• Opera extensions developer workflow

UI guidelines and distribution

• Publishing guidelines
• Creating effective Opera Extension icons
• Distributing Opera extensions and auto-updates

API reference

You can build Opera extensions using the Opera Extensions APIs and open web standards like JavaScript and HTML. This makes Opera extensions easy to create, quick to debug, and fast to install.

Basics and UI elements:

• config.xml (defining the extension)
• Metadata and preferences
• Button and badge
• Popup window
• Windows & Tabs

Browser functions:

• Injected scripts (add JavaScript to websites)
• URL filtering (e.g. for ad blocking)
• Messaging (e.g. between the background process and the injected script)
• Speed Dial (for Speed Dial extensions)
• Resource Loader (access any file within an extension package)
• Screenshot (take screenshots of pages)
• Context Menu (add items to the context menu)

Finishing up:

• Adding an options page
• Packaging your extension
• Publishing it to the Opera extensions catalog

Extension tutorials

• The ins and outs of config.xml
• Buttons, badges and popups
• Interacting with browser tabs
• Interacting with browser windows
• Messaging
• Options page
• Accessing an Opera extension's background process
• Creating Opera Speed Dial extensions
• Cookie-sharing in Opera extensions
• Site blocking with Opera's URL Filter API
• Creating multilingual extensions
• Hands-on tutorial: building an Opera extension

Templates and code samples

• Opera extension code examples
• Opera extensions prototypes for modifying CSS
• Speed Dial extension boilerplate (Github)
• Turn your RSS into a live Opera Speed Dial extension