Create addon_communication.markdown

source/developers/hassio/addon_communication.markdown

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+---
+layout: page
+title: "Add-On Communication"
+description: "Describe internal communication Hass.io."
+date: 2017-04-30 13:28
+sidebar: true
+comments: false
+sharing: true
+footer: true
+redirect_from: /hassio/addon_config/
+---
+
+It exists diferent ways to communication between add-ons or home-assistant inside Home-Assistant.
+
+## {% linkable_title Network %}
+
+We use a internal network. That allow to speak with every add-on or from Home-Assistant to add-on by name or alias. Only the a add-on they run on Host network are a bit limited. They can speak with all internal add-ons over there name but all other add-on can't speak with the add-on name to this add-on, but alias work wheel. So use the name/alias to communicate inside Hass.io
+
+i.e. use `hassio` to speak with internal API.
+
+## {% linkable_title Home-Assistant %}
+
+A Add-on can speak to [Home-Assistant API][hass-api] with our internal proxy. That make it very easy to speak to this API without you need know the password, port or any other information for the Home-Assistant instance. Use this url: `http://hassio/homeassistant/api` and they will internal redirected to the right place. As next add `homeassistant_api: true` to `config.json`.
+
+It is also possible to speak direct to Home-Assistant instance with name `homeassistant` over our internal Network. But you need know the running config.
+
+## {% linkable_title Hass.io API %}
+
+
+[hass-api]: https://home-assistant.io/developers/rest_api/
+[hassio-api]: https://github.com/home-assistant/hassio/blob/master/API.md