> Source: https://builder-docs.ema.ai/core-concepts
> Title: Core Concepts

# Core Concepts

This section covers the foundational concepts of the Ema Builder Platform. Understanding these concepts is essential before building or customizing AI Employees.

## Platform Fundamentals

-   [AI Employees](/legacy-docs/core-concepts/ai-employees) -- What AI Employees are, their lifecycle, interface types, and how they differ from traditional automation.
-   [AI Employee Groups](/legacy-docs/core-concepts/ai-employee-groups) -- Organizing AI Employees into groups for easier navigation and management.
-   [Workspaces and Tenants](/legacy-docs/core-concepts/workspaces-tenants) -- Multi-tenant architecture, workspace isolation, partner-customer hierarchy, and tenant management models.
-   [Projects](/legacy-docs/core-concepts/projects) -- Project-based workflows for campaign, recruitment, document generation, and other multi-step processes.
-   [Frontier Apps](/legacy-docs/core-concepts/frontier-apps) -- Deploying custom web applications that connect to AI Employees via the Ema platform.

## Generative Workflow Engine (GWE)

-   [GWE Overview](/legacy-docs/core-concepts/gwe-overview) -- What the Generative Workflow Engine is, the visual canvas, code view, and how workflows execute as DAGs.
-   [Workflows and Actions](/legacy-docs/core-concepts/workflows-actions) -- Workflow structure, action types, the DAG execution model, and how actions compose.
-   [Named Inputs and Outputs](/legacy-docs/core-concepts/named-inputs-outputs) -- The preferred data-passing protocol for flexible, multi-output workflows.
-   [Conditionals](/legacy-docs/core-concepts/conditionals) -- Boolean trigger-when expressions, skip propagation, optional agents, and branching patterns.
-   [Type System](/legacy-docs/core-concepts/type-system): Well-known types, array types, and enumerations.
-   [Workflow Validation](/legacy-docs/core-concepts/workflow-validation) -- Static validation, path enumeration, and ensuring all paths produce required outputs.
-   [Workflow Version History](/legacy-docs/core-concepts/workflow-version-history) -- Tracking changes to workflow definitions over time and reverting to previous versions.

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> For internal implementation details (Temporal orchestration, gRPC contracts, data models, and protocol internals), see the internal core concepts supplement.