Process Concepts

The runtime concepts that show up everywhere in Conduit: process variables and the FEEL expression language. The per-element pages reference these — read them once and the rest of the docs sit on top.

Pages in this section

Variables & Scopes

What a process variable is, where it lives in the database, what the “Scope” column on the instance log means, and how variables flow across executions, parallel branches, and embedded subprocesses. Also: the two system-injected identifiers (instanceId, instanceCounter) you can always reference from FEEL.

Expressions (FEEL Cookbook)

Practical FEEL patterns for the places where expressions actually run in a process: gateway conditions, script tasks, decision input/output. Counters, accumulators, null-safe access, list building, conditional writes. Pairs with the FEEL Reference which is the full syntax index.

Why these are concepts, not elements

A BPMN element (a task, a gateway, an event) is a thing on the canvas. Variables and expressions cut across all of them — every flow node either reads or writes variables, and every condition is a FEEL expression. Grouping them here keeps the per-element pages focused on element-specific semantics rather than re-explaining the runtime each time.