JSONPress

JSONPress – Allows you to request WordPress site via JSON/JSONP output using standard WordPress query.

Features

• Access JSON via sub domain, ex. api.example.com (sub domain must be configured separately)
• Supports JSONP callback.
• Easy to debug output using JSON pretty print or print_r.
• You can exclude columns/data to be displayed in JSON output.
• You can include custom fields too.
• This plugin uses standard WordPress query, no SQL hack etc.
• Use standard WordPress URL, no need to remember new annoying URL.
• And many more features I don’t tell here.

Special

Not only posts/page, you can also call some functions via URL.

Examples:

• example.com/get/wp_list_categories to displays list categories in JSON format
• example.com/get/wp_list_pages to displays list pages
• example.com/get/wp_nav_menu to displays menus

Hei, how about $args of those functions?
* example.com/get/wp_list_categories?args[orderby]=ID&args[exclude]=1,3,4&args[child_of]=2 etc. cool, right?
* Use subdomain API is recommended to ensure all links/permalinks are rewritten to API URL.