Which of the following is NOT a user role in ArcGIS Online?

In ArcGIS Online, user roles define the level of access and capabilities each user has within the platform. The roles include Administrator, Creator, and Editor, each providing specific permissions tailored to different responsibilities and tasks.

The Administrator role has full access to manage the organization, including user management, content management, and settings. The Creator role allows for extensive capabilities, enabling users to create and publish content such as maps and layers while also having access to advanced tools. The Editor role provides access primarily to edit existing content and collaborate on projects.

The term "Developer," while associated with roles in various software environments, is not a specific user role within ArcGIS Online. Instead, developers typically leverage the ArcGIS platform's APIs and SDKs to build applications but do not fall under the officially designated user roles within the organizational structure of ArcGIS Online. This distinction makes "Developer" the correct answer, as it is not an official role defined by Esri within the ArcGIS Online environment.