SharePoint: SharePoint hosted ,Auto hosted, Provider hosted apps in SharePoint 2013

App Hosting Options in SharePoint 2013:

These types of apps are hosted on SharePoint itself. All code runs on SharePoint server.
SharePoint-hosted apps for SharePoint are installed on a SharePoint 2013 website, called the host web, and that have their resources hosted on an isolated sub site of a host web, called the app web
No server side code is allowed. Only JavaScript and HTML code can be written for logic and User interface.
Java script library for SharePoint (JSOM) can be used to access SharePoint lists, libraries etc.
SharePoint hosted Apps are always scoped at web level and cannot exchange information with other apps.

2. Cloud Hosted Apps:

Cloud hosted apps are hosted on other servers such as IIS, windows azure etc. so In cloud hosted apps code runs outside SharePoint ,infrastructure chosen by you(either windows azure or some other server).
We can write server side code in cloud hosted Apps.
Cloud hosted Apps can be of two types:-

Provider hosted apps:-

In Provider Hosted app we have choice of infrastructure to host our app such as IIS websites, or third party cloud or non-Microsoft technologies as well.
Dedicated server/hosting service is needed to host our app, so we have full control over it.
Every time user installs an app, each request goes to same site on server which has hosted the app.
Developer is responsible for Multitenancy.

Auto Hosted apps:-

In Auto Hosted, app is hosted on windows azure site automatically.
Multitenancy is provided by default.
Every time user installs an app, web (Windows azure web site) and SQL azure components are provisioned automatically which handles load balancing, multi-tenancy tasks.

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