Plugins are packaged customization files that can be imported into your kintone environment, and installed into any number of your apps.
Plugins provide an easy way for users to set up their customization without having to alter any codes.
The other files make up the Plugin Settings page - this is where users can input custom variables that will change the behavior of the Plugin.
Do you have any Samples?
We currently have plug-ins for Mandrill, Dropbox, Zendesk and Box.
Feel free to download, and install it into your kintone environment.
You will need an account for those services for the integration to work well.
We will be bring out more samples and post them on the kintone developer network.
Can I make my own Plug-ins?
Please go ahead, and create your custom plugins.
Get your environment ready by reading through Plugin Development Environment.
Follow on to read through Steps for Plugin Development to understand how Plugins are structured.