There are six API categories:

• Client: Client-side API for desktop apps
• Client Mobile: ServiceNow Classic mobile application API. Not for ServiceNow Agent, Now Mobile, or ServiceNow Onboarding
• Now Experience UI Framework: Agent Workspace component API
• Server Scoped: Scoped application API for server-side
• Server Global: Global application API for server-side
• REST: Restful APIs for interacting with a ServiceNow instance

For most methods the API reference documents include:

• Method name
• Method description
• Return data type
• Return data description
• Example script