ArcGIS Enterprise, which includes Portal for ArcGIS, and organizational subscriptions to ArcGIS Online are complementary implementations of Web GIS. They provide similar functionality, such as a portal website with map and scene viewers, a content repository, and the same API for developers. However, the infrastructure they run on is managed differently.
With ArcGIS Online, all components run in Esri-managed cloud infrastructure in a Software as a Service (SaaS) model. In other words, the compute and data storage resources, the website, and every other aspect of the system is hosted by Esri in a highly scalable environment. You use ArcGIS Online to create, use, and share maps and apps with your organization and the public.
ArcGIS Enterprise provides similar capabilities as ArcGIS Online, but it runs on your infrastructure. This infrastructure can be owned and operated directly by you or, optionally, infrastructure managed by other cloud providers, such as Amazon Web Services or Microsoft Azure. You use ArcGIS Enterprise to create, use, and share maps and apps within your enterprise.
Portal for ArcGIS is also the entry point for using ArcGIS Pro to publish certain types of GIS services to your ArcGIS Server sites, such as 3D scene layers.
Organizations typically implement ArcGIS Enterprise when they have one or more of the following requirements:
- They require full control over the hardware running the portal in order to maintain a particular service-level agreement (SLA).
- They require service publishing from the website, and enterprise data is prohibited from being physically stored off-premises.
- Computers in the organization are not connected to the Internet or have an unreliable Internet connection.
- They want to use functionality available only with Portal for ArcGIS and ArcGIS Pro, such as publishing their own 3D scene layers.
Many ArcGIS platform customers use both ArcGIS Online and ArcGIS Enterprise to achieve a comprehensive and robust system for managing all their geospatial assets. In this way, they can completely support both internal and external stakeholders and workflows in a secure, scalable, and flexible environment.
For additional implementation considerations and best practices, see Architecting the ArcGIS Platform: Best Practices.