Set Variable

Stores a workflow-scoped variable. Use this for counters, accumulators, or "carry this forward" values that need to be referenced by later nodes — without threading them through every edge.

Variables live for the duration of an execution and are isolated per execution. They are deleted when the workflow completes successfully.

Reading variables

Once set, a variable can be referenced anywhere a template expression is allowed:

{{ vars.counter }}
{{ vars.user.email }}

The Code node also exposes vars as a read-only object in its expression environment.

Configuration

Field	Description	Notes
Operation	What to do with the variable	Set, Increment, Append, Merge, Delete. Defaults to Set.
Variable Name	Name of the variable	Required. Templates allowed — e.g., counter_{{data.region}}.
Value	The value to store	Required for Set/Append/Merge. JSON-parsed (so 42, true, "hi", [1,2], {"a":1} all work). Bare strings without quotes pass through as plain strings.
Increment By	Amount to add	Increment only. Defaults to 1.

Operations

Set

Replace the variable's value. The previous value is overwritten.

Increment

Atomically add a number to a numeric variable. Safe to use from parallel branches — Redis guarantees atomicity. Starts from 0 if the variable doesn't exist.

Append

Push a value onto an array. Creates the array containing the value if the variable doesn't exist.

Merge

Shallow-merge an object into an object variable. Keys in the new value overwrite existing keys.

Delete

Remove the variable entirely.

Examples

Counter incremented per processed item

Inside a loop / per-item branch, place a Set Variable node with:

• Operation: Increment
• Name: processed
• Increment By: 1

Then reference {{ vars.processed }} in a downstream Email or Slack node.

Aggregate scores from a stream

• Operation: Append
• Name: scores
• Value: {{data.score}}

After the loop, the Code node can sum them: sum(vars.scores).

Track a running config object

• Operation: Merge
• Name: config
• Value: {"region": "eu", "tier": "premium"}

Lifetime

Event	Variables behavior
Workflow completes successfully	Variables are deleted.
Workflow fails or pauses	Variables persist for 24 hours so the run can be resumed.
Each operation	The 24-hour TTL is refreshed.

WARNING

Variables are per-execution. They are not shared across separate runs of the same workflow. To share state between runs, use the DataStore nodes or an external database.