The omnibox API allows you to register a keyword with Google Chrome's omnibox.

When the user enters your extension's keyword, they enter a mode where they are interacting solely with your extension. Each of their keystrokes is sent to your extension, and you can provide suggestions in response.

The suggestions can be richly formatted in a variety of ways. When the user accepts a suggestion, your extension is notified and can take action.

Manifest

To use the Omnibox API, your manifest must declare the "experimental" permission and register an omnibox keyword. You should also specify a 16x16-pixel icon. This will get displayed in the omnibox when suggesting users enter keyword mode.

For example:

{
  "name": "Aaron's omnibox extension",
  "version": "1.0",
  "permissions": ["experimental"],
  "omnibox_keyword": "aaron",
  "icons": {
    "16": "16-full-color.png"
  },
  "background_page": "background.html"
  
}

Note: Google Chrome automatically creates a greyscale version of your 16x16-pixel icon. You should provide a full-color version so that it can also be used in other situations that require color. For example, the Context Menus API also uses a 16x16-pixel icon, but it is displayed in color.

Examples

You can find samples of this API on the sample page.