User

A User in Salesforce is a standard object that represents an individual login account in the org - every person who signs into Salesforce has exactly one User record. The User object stores authentication and profile data including username, email, name, alias, time zone, locale, federation ID, and the assigned Profile that controls baseline permissions. Each User is also associated with a Role (for record sharing), one or more Permission Sets and Permission Set Groups (for additive access), a User License (which determines available features and pricing), and a manager (for hierarchy-based reporting and approvals). Users own records - almost every standard and custom object has an OwnerId field that references a User. Beyond standard logins, the User object also represents Customer Community Users, Partner Users, Guest Users, Site Users, Integration Users, and Automated Process Users, each tied to a specific User License type. Active User counts directly drive Salesforce billing, so admins must deactivate (not delete) departed users to free up licenses while preserving historical record ownership.

The User object is unusual because it's both a standard sObject (queryable via SOQL, updatable via API, capable of having custom fields) and a security primitive that the platform itself depends on. Updates to User records run through extensive backend validation - license assignment, sharing recalculation, profile permission propagation - meaning bulk operations on Users are slow and have stricter governor limits than most objects. Apex code that needs to run as another user often uses System.runAs() in tests or sets a record's OwnerId rather than directly impersonating.

Deactivating a User (IsActive = false) is the correct way to remove access - Salesforce blocks hard deletion of User records that own data, since OwnerId references would break referential integrity. Deactivated Users free their license seat for reassignment, but their historical record ownership remains intact. Reactivating a User restores access without recreating the account. For role changes or department transfers, edit the existing User rather than creating a new one - this preserves the audit trail of every Activity, Case, and Opportunity they touched.

Beyond internal employees, the User object also represents external personas through different License types: Customer Community Plus Users, Partner Community Users, Guest Site Users (used by unauthenticated public visitors to Experience Cloud sites), Integration Users (typically a single dedicated User per external system), and Automated Process Users (system identity for Flow, Process Builder, and platform background jobs). Each carries different sharing implications, costs, and feature access - choosing the wrong license type for a use case is one of the most expensive misconfigurations in Salesforce.