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Variables defined in this node exist only during the current execution. They do not persist between separate runs of the same workflow.

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How It Works

The Set Variable node creates or overwrites variables scoped to the current execution. Once defined, they are accessible in all downstream nodes via {{ $vars.variable_name }} — including condition nodes, HTTP nodes, JavaScript code nodes, and the LLM node prompt. Use the node to:
  • Extract fields from a large payload and give them clear, short names
  • Calculate or concatenate values derived from multiple flow sources
  • Store intermediate results that will be consumed by more than one downstream node
  • Initialize counters, flags, or control objects before entering a loop

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Configuration Options

A single node can define as many variables as needed. Each variable requires three fields:
  • Name — snake_case identifier with no spaces; after typing, the panel displays the access expression {{ $vars.your_name }}
  • Type — determines how the value is stored and interpreted by the execution engine
  • Value — static field, dynamic reference via {{ }} template, or block editor for JSON
TypeWhen to use
stringText, IDs, names, emails, alphanumeric values
numberQuantities, totals, indices for calculations and comparisons
booleanControl flags (true / false) for conditionals
jsonComplex objects or arrays to be passed to the HTTP or LLM node
expressionFull dynamic template — the entire value is resolved at runtime

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Common Use Cases

The Set Variable node is most useful in the following patterns:
  • Rename payload fields — an external webhook arrives with keys in a different language or format (customer.full_name, order.ref); define variables with clearer names before referencing them in downstream nodes, making the flow more readable
  • Build an HTTP request body — assemble a complex json object with fields from different parts of the flow ($trigger, $json, other $vars) and reference the variable as {{ $vars.payload }} in the HTTP node’s body field
  • Control loop iterations — initialize counter as a number with value 0 and error_list as json with value [] before the Loop node; the internal JavaScript node updates these values on each iteration using vars.counter and vars.error_list