We provide authorization mechanism based on OAuth2.0.
With TwitCasting OAuth, your application is able to make REST API calls with the end user's permission.
First, you should create a new application on Developer Page. Hit "Create New App" and fill out information.
Once you got ClientID, ClientSecret, you can acquire access token by making an OAuth client.
Finally, with the access token you should be able to fetch JSON responses from REST APIs.
See APIv2 Documentation, CHANGELOG, @twitcasting_dev, though currently written in Japanese.