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The Transform node runs operations that read from and write to the session context. Use it for data shaping, cleanup, combining fields, accumulating results across a loop, or execution-state updates. Each operation has a type, a target dot-path under context.*, and (for non-DELETE ops) a value that is a raw JSONata expression. Operations in the same node run top-to-bottom and each one sees the writes of the ones before it.
The value field is raw JSONata, not a template. Do not wrap it in {{...}} — reference variables directly (e.g. context.inputs.email ~> $trim, not {{context.inputs.email}} ~> $trim).

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Parameters

ParameterTypeRequiredDescription
operationsarrayYesOrdered list of operations, each { type, target, value? }

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Operation Fields

FieldTypeRequiredDescription
typestringYesSET or DELETE
targetstringYesDot-path under context.* where the result is written. Missing intermediate objects are auto-created
valuestringYes (except DELETE)Raw JSONata expression evaluated against the session context

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Operation Types

TypeSemantics
SETAssign the evaluated value to target, creating the path if it doesn’t exist
DELETERemove the value at target. value is ignored
For object-merging and array manipulation, use SET combined with JSONata’s built-in $merge and $append functions — there is no dedicated merge or append operation type.
WantUse
Shallow-merge an object into a targetSET context.x = $merge([context.x, {new_field: 'value'}])
Flat-concatenate two arraysSET context.combined = $append(context.a, context.b)
Append one element to an arraySET context.results = $append(context.results, [item])

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Examples

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Normalize an Input

Clean up an email before typing it into a form: 
{
  "id": "abc123",
  "name": "Normalize email",
  "action": "TRANSFORM",
  "parameters": {
    "operations": [
      {
        "type": "SET",
        "target": "context.email_clean",
        "value": "context.inputs.email ~> $trim ~> $lowercase"
      }
    ]
  }
}
Reference it downstream with {{context.email_clean}}.

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Combine Fields

Derive a full name from two inputs: 
{
  "id": "abc123",
  "name": "Build full name",
  "action": "TRANSFORM",
  "parameters": {
    "operations": [
      {
        "type": "SET",
        "target": "context.full_name",
        "value": "context.inputs.first & ' ' & context.inputs.last"
      }
    ]
  }
}

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Combine Two Arrays

Flat-concatenate two arrays using JSONata’s $append: 
{
  "id": "abc123",
  "name": "Combine arrays",
  "action": "TRANSFORM",
  "parameters": {
    "operations": [
      {
        "type": "SET",
        "target": "context.combined",
        "value": "$append(context.inputs.array1, context.inputs.array2)"
      }
    ]
  }
}
$append([1, 2], [3, 4]) produces [1, 2, 3, 4]. Note that & is string concatenation in JSONata, not array — use $append for arrays.

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Accumulate Loop Results

Inside a loop body, append processed items into an array using $append: 
{
  "id": "abc123",
  "name": "Collect order summary",
  "action": "TRANSFORM",
  "parameters": {
    "operations": [
      {
        "type": "SET",
        "target": "context.collected_orders",
        "value": "$append(context.collected_orders, [{'id': context.runtime.current_order.id, 'total': $number(context.runtime.current_order.amount)}])"
      }
    ]
  }
}
The single-element array ([{...}]) wrapping is what makes $append flat-concatenate one item — passing the bare object would also work ($append flattens), but the array form makes intent obvious.

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Enrich an Extracted Object

Add metadata to a record that was extracted earlier: 
{
  "id": "abc123",
  "name": "Tag with source",
  "action": "TRANSFORM",
  "parameters": {
    "operations": [
      {
        "type": "SET",
        "target": "context.extracted_profile",
        "value": "$merge([context.extracted_profile, {'extracted_at': $now(), 'source': 'crm'}])"
      }
    ]
  }
}

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Clean Up Before End

Drop scratch paths so they don’t show up in the webhook payload: 
{
  "id": "abc123",
  "name": "Clean scratch",
  "action": "TRANSFORM",
  "parameters": {
    "operations": [
      { "type": "DELETE", "target": "context.internal_scratch" },
      { "type": "DELETE", "target": "context.tmp_html" }
    ]
  }
}

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Notes

  • Targets must start with context.. Anything else is rejected by validation because downstream nodes can’t read it.
  • Later operations in the same node see earlier writes, so you can derive values in stages within one Transform.