Preview a poll delivery's jsonata_expression without saving or enqueueing anything. The expression is checked and evaluated exactly as at enqueue time: the same length, syntax and binding checks, the same $env/$mapValue/$mapKey bindings resolved server-side from the org's non-secret environment variables and key/value maps, the same evaluation limits, and the same rule that the output must be a JSON object.

Provide exactly one input: payload (an event to map as-is), or event_id (with event_catalog_event) to load a historical event-catalog event and hydrate it exactly as enqueue does — the preview is then exact, and the hydrated event is echoed as input.

Mapping failures are a 200 with valid: false and an error; 4xx is reserved for malformed requests. Requires the integration:view grant.

{
  "jsonata_expression": "{ \"contract_number\": contract.contract_number, \"status\": $mapValue($env.erp.statuses, contract.status) }",
  "event_catalog_event": "contract.updated"
}

{
  "mapping_version": "3f2a9c1b7d4e8f60"
}