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Mapper Connector
Map JSON data field by field to a new shape with built-in transforms, a JSONata escape hatch per field, and post-mapping validation that can halt the workflow.
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What this connector is for
Maps JSON data field by field into a new shape. Each row names a source path to read, an optional transform, and a target path to write, plus optional per-field validation that can halt the workflow on a bad result. It sits between two adjacent connectors: JSONata is a single freeform expression with no built-in validation, and Schema Validator validates a whole document but never reshapes it. Mapper does structured row-by-row reshaping, and a row's JSONata-kind transform gives you an escape hatch when a built-in transform isn't enough.
Every action, with its fields and the built-in transform list, is in the action reference.
Mapping conventions
- Paths use dot notation (
items.data.request.age) and bracket indices (items[0].tags). - An
arrayGrouprow maps an array item by item. Its nestedmappingsresolve relative to each source array item, so one row reshapes every element without listing an index. - A
fieldrow with a blank source path and adefaultValuetransform injects a constant. - A JSONata transform sees the resolved source value as
$valueand the current source scope (the array item, inside an arrayGroup) as$item, for example$value & " (" & $item.status & ")". - Skip if Missing defaults to
true: an undefined source omits the target field. AdefaultValuetransform still runs regardless. - Validation is checked against the mapped value after the whole mapping walk completes, so a
requiredcheck never fails because a later rule hasn't written a sibling yet.
Map Fields
On Validation Error is halt (default) or collect, and both modes also catch transform failures such as toNumber on a non-numeric string.
haltstops the workflow with an HTTP-style error response (configurable status, default 400, body, and headers;{{errors}}in the body is replaced with the JSON error array), like Schema Validator.collectcontinues and exposes every error throughvalidationErrorsandhasValidationErrors.
The response shape differs by outcome:
- Success, or collect mode with errors: the mapped object is at
{{<stepReference>.response.data.data}}. In collect mode with errors,{{<stepReference>.response.data.validationErrors}}(array of{ruleId, sourcePath, targetPath, message, keyword}) andhasValidationErrorsare also present. - Halt mode failure: spread flat, with
{{<stepReference>.response.status}},{{<stepReference>.response.data}}(the error body), and{{<stepReference>.response.validationErrors}}as a sibling ofdata.
So for a step named "Map Order" (reference mapOrder), use {{mapOrder.response.data.data.orderId}} on success, and check {{mapOrder.response.status}} to detect a halt.
Preview Mapping
Runs the same engine as Map Fields against sample data but never halts the workflow, and has no Options field. It always returns the plain result shape (data.data, plus validationErrors and hasValidationErrors only when errors occurred). Use it to test a mapping in the designer before wiring it into a real step.
Your first call
- Add a Map Fields step named "Map Order" with Input Data
{{trigger.body}}. - Add rows:
order.idtoorderId;order.amounttototalwith transformtoNumber; a blank source tocurrencywith transformdefaultValue("USD"). - For input
{"order": {"id": "abc123", "amount": "42.50"}},{{mapOrder.response.data.data}}is{"orderId": "abc123", "total": 42.5, "currency": "USD"}.
Also applies here
Step Name
What it's for
Every step in a workflow gets a name — either one you set or a default based on the connector and action (e.g. "Get Order Details", "Send Welcome Email"). It's shown throughout the UI and in your execution history, and it's also the source for the step's Reference — a camelCase identifier auto-generated from the name (e.g. "Get Order Details" → getOrderDetails) — which is what you actually use in {{...}} expressions to read this step's output from later steps. See Step Reference.
Rules
- Must be at least 2 characters, and 50 characters or fewer.
- Must be unique within the workflow — reusing a name that's already taken will be rejected, with a suggested alternative (e.g.
"Get Order Details 2"). - Can't be empty.
Tips
- Prefer a descriptive, human-readable name over a generic one — "Get Order Details" is easier to work with later than "HTTP Request 2", especially once a workflow has a dozen steps.
- Renaming a step updates every reference to it elsewhere in the workflow automatically.
Step Reference
Syntax
Any input field can reference earlier data using {{expression}}. The expression is evaluated as JSONata — so simple dot-paths and more advanced queries (filters, functions) both work.
Referencing a step's output
Use the step's Reference — a camelCase identifier auto-generated from its Name (e.g. "Get Order Details" → getOrderDetails), shown read-only wherever the step's fields are configured — followed by the field path. Elsewhere in these docs this general pattern is written as {{<stepReference>.field.path}}:
{{getOrderDetails.response.data.id}}
{{getOrderDetails.response.status}}
The raw display name won't work here even though it's what you see in the UI — {{Get Order Details.response.data.id}} isn't valid, since a bare name containing spaces isn't a single JSONata identifier. Always use the camelCase Reference.
You can also reference steps by position instead of by reference:
{{steps[0].response.data.id}}
Referencing trigger data
{{trigger.headers.authorization}}
{{trigger.body.customerId}}
{{trigger.query.page}}
{{trigger.params.orderId}}
{{trigger.method}}
{{trigger.path}}
Referencing workflow variables
{{variables.myVariable}}
See Variables for the full list of variable types and more examples, including connection-type variables.
Referencing runtime variables
A separate, mutable namespace written by the Variable connector while a run is in progress — not the same as the workflow-level variables above:
{{runtimeVariables.myVariable}}
Notes
- If an expression can't be resolved (a typo in a step name, a field that doesn't exist), it resolves to an empty string rather than failing the workflow — check your execution history if a value comes through blank.
- Object values are automatically JSON-stringified when interpolated into a string field.
Execution Settings
Fire-and-forget
When enabled, the workflow doesn't wait for this step to complete before moving to the next one. Use it for steps whose result nothing downstream depends on — logging, analytics, notifications — so they don't add latency to the steps that matter.
Continue on error
When enabled, a failure in this step doesn't stop the workflow — execution continues to the next step. The failure is still recorded in the execution history; this just controls whether it's fatal.
Combine the two for steps that are genuinely optional to the outcome: fire-and-forget so they don't add latency, continue-on-error so a failure in them (e.g. an analytics endpoint being briefly down) doesn't take down an otherwise-successful workflow run.
Caching
What it does
When enabled, a step's result is cached for a configurable TTL (time-to-live, in seconds). If the step runs again with the same effective cache key before the TTL expires, the cached result is returned instead of re-running the step.
Configuring it
- Enabled — turn caching on or off for this step.
- TTL — how long (in seconds) a cached result stays valid.
- Cache key template — an expression (supporting the same
{{...}}step reference syntax used elsewhere) that determines what counts as "the same call". By default this is based on the step's resolved input; a custom template lets you cache more narrowly or broadly than that.
When to use it
Good candidates are steps that call something slow or rate-limited but return the same answer for the same input within a short window — a lookup against a rarely-changing external system, for example. Skip it for steps whose result must always be fresh (anything involving live inventory, pricing, or payment state).
Last updated 9 October 2026