Portal for ArcGIS and organizational subscriptions to ArcGIS Online provide similar functionality such as a website, a map viewer, a content repository, and an API; however, they run in different environments. With ArcGIS Online, these components run in an Esri-administered cloud infrastructure, whereas with Portal for ArcGIS, these components run on your own hardware.
With ArcGIS Online, you will be up and running quickly without installing software or procuring additional hardware. Many organizations achieve success by running ArcGIS for Server behind their firewalls and sharing their services, apps, and maps through an ArcGIS Online organizational account. Others use ArcGIS Online to host basic services without any need for an on-premises GIS server.
Portal for ArcGIS allows you to more tightly integrate with your GIS server and your network environment. Portal for ArcGIS is a more appropriate choice than ArcGIS Online if any of the following conditions exist:
- You require full control over the hardware running the portal in order to maintain a particular service level agreement (SLA).
- You will allow service publishing from the website and your data is prohibited from being physically stored off-premises.
- Computers in your organization are not connected to the Internet or have an unreliable Internet connection.
Some capabilities such as sharing the security settings of your organizational users and your ArcGIS Server site, are only possible in Portal for ArcGIS.
Conversely, some new features that you see in ArcGIS Online may not be immediately available in Portal for ArcGIS. For example, improvements in the ArcGIS.com viewer to access analytical tools and work with image service layers will only be available in later releases of Portal for ArcGIS.