Expression

Workflow reference | Complete expression catalog

Kind: Expression
Configuration object: expression

Use Expression for deterministic local transformations, field selection, arithmetic, encoding, validation, and specialized retrieval or evaluation processing. This step requires no provider credential.

Inputs

Receives typed input, named incoming bindings, and established variables. A root Expression receives the workflow input. At a join, use named bindings to retain the original types of different sources.

Configuration

These properties belong directly to the node's expression object. Use the expression reference for every function, allowed arity, output type, and error condition. The visual editor shows a readable formula for the configured tree.

Outputs

The function's typed result becomes the output. Strings are displayed as ordinary text; objects and arrays are serialized as JSON. JSON null is valid and displayed as null. Downstream expressions receive the original type.

Malformed inputs, missing root bindings, invalid types, failed assertions, and size/depth violations fail the step and the run. Expressions never execute arbitrary source code.

Example

{
  "id": "select-total",
  "name": "Select the order total",
  "kind": "Expression",
  "outputName": "total",
  "expression": {
    "function": "get",
    "value": "order.total",
    "arguments": [
      { "function": "input", "value": "input" }
    ]
  }
}

With input {"order":{"total":125.5}}, this produces numeric 125.5. Use Condition for branch routing, or an edge transformation for a change needed by only one consumer.