validation_logic

validation_logic is a JSONLogic predicate evaluated before workflow execution on every ingress. A truthy result admits the request; a falsy one rejects it with 400 Bad Request. JSONLogic truthiness applies: false, null, 0, "", and [] are falsy.

Synopsis

{
  "validation_logic": {
    "and": [
      { "!!": [{ "var": "data.order_id" }] },
      { ">": [{ "var": "data.amount" }, 0] }
    ]
  }
}

Fields

Context. The expression evaluates against exactly { "data": …, "metadata": … }. data is the request payload as submitted. The guard runs before any workflow task, so data.order_id resolves here even though the workflow itself reads the payload only after parse_json. metadata has the same shape the workflow’s data context carries (headers, query, path params, channel name; transport-dependent). See the Workflow Schema. On Kafka, metadata carries the record coordinates and no headers.

Rules:

• An expression that cannot be evaluated against a request rejects it with the same opaque 400 — the detail is logged, not returned, because the data plane is anonymous.
• A validation_logic that does not compile quarantines the channel at load.
• Payload size is bounded globally by ingest.max_payload_size, not per channel.

Related

• Expression language: every operator the predicate may use.
• Configure a channel: adding a guard in practice.
• Workflow definition › The data context: the metadata shape the predicate reads.
• Channel configuration: every key, with its page.

Last verified 14 September 2026