A browser synchronizer is a tool or an extension which allows users to keep their web browser configured in the same way on different computers or operating systems. For instance, if a user adds a bookmark while being at home, the bookmark will be available the day after at office. Depending on the tool's features, bookmarks, preferences, extensions and GUI can be preserved.
Such functionality is usually available by using third-party plugins. As of version 9.5, the Opera browser has this functionality built-in, and also offers synchronization of bookmarks and other data between desktop computers, and mobile phones running Opera Mini.