# Glossary

- **Batch Processing**: Executing multiple workflow runs over varying inputs, typically via queues or Drupal Batch API.
- **Checkpoint**: A saved snapshot of workflow execution state, used by the StateGraph orchestrator to resume workflows after interruptions or failures.
- **Data Edge**: An edge that passes data from one node’s output port to another node’s input port; does not control execution flow.
- **Edge**: A connection between two nodes that carries either data or execution control signals. See also *Data Edge* and *Trigger Edge*.
- **Execution Session**: A single run of a workflow carrying transient context (inputs, intermediates, outputs) across nodes.
- **Gateway Node**: A diamond-shaped node that creates branching logic in a workflow (e.g., IfElse, SwitchGateway). Evaluates a condition and activates one or more output branches.
- **Idempotency**: Re‑running a node with identical inputs/config yields the same state and side‑effects.
- **Interrupt**: A pause in workflow execution that requests user input. Types include confirmation, choice, text input, and form input. See the [Human-in-the-Loop guide](../guide/human-in-the-loop.md).
- **Job**: One node’s execution within a pipeline. Records the node’s input, output, status, and timing.
- **Loopback Edge**: A special edge type for loop iteration; connects loop body output back to iterator node; excluded from dependency checking and cycle detection.
- **Node**: A single step in a workflow. Each node has typed input ports, output ports, and configuration parameters.
- **Node Processor**: The backend component that executes a node; should be idempotent and deterministic.
- **Node Type**: A configurable wrapper around a Node Processor. A single processor can have multiple Node Types with different default settings.
- **Orchestrator**: Controls how a workflow runs — synchronous (immediate), asynchronous (background queue), or StateGraph (stateful with loops and pauses). See [Execution Modes](../guide/execution-modes.md).
- **Pipeline**: One complete run of a workflow. Contains individual jobs for each node that executes.
- **Playground**: An interactive chat-based interface for testing workflows. See the [Playground module](../modules/flowdrop_playground.md).
- **Port**: A connection point on a node where edges attach. Input ports are on the left, output ports on the right. Ports are color-coded by data type.
- **Queue Processing**: Offloading long‑running or asynchronous execution to Drupal’s Queue API or cron workers.
- **Session**: A multi-turn interaction context for interactive workflows. Tracks message history and state across multiple exchanges.
- **Trigger**: An event-driven configuration that automatically starts a workflow when something happens in Drupal (entity changes, user events, cron). See [Setting Up Triggers](../guide/triggers.md).
- **Trigger Edge**: An edge that controls execution flow; connects to a node’s trigger input port to determine if/when the node executes.
- **Workflow**: A directed graph of steps that transforms inputs into outputs within a defined context.
- **Workflow Node**: A discrete, reusable step with typed inputs, typed outputs, and configuration.
