Start Node
The Start node is the entry point of a workflow graph. It receives the trigger payload and hands it to the first downstream node through the normal cascade.
Start is inserted automatically when you create a new workflow and does not appear in the node palette — you cannot drag one onto the canvas.
When to use
Section titled “When to use”Every top-level graph needs exactly one Start node. You do not need to add one inside a fan-out template — templates use their In/Out markers instead, and Start/End nodes are rejected inside templates.
Configuration
Section titled “Configuration”| Field | Description |
|---|---|
input_contract (optional) | Name of a contract that incoming trigger payloads must satisfy. Unset means any payload is accepted; cron-triggered runs always pass {}. |
The contract is selected from the contracts defined on the graph. Payloads that fail validation are rejected with HTTP 400 before the run even starts.
Payloads arrive from a manual run, from a cron schedule (always {}), or from an outside caller over a webhook URL.
Behavior
Section titled “Behavior”- When the workflow is triggered, the Start node is inserted as
completedwithoutput_dataset to the trigger payload. - It immediately fires cascade to its downstream successors, who read the payload as their input.
Start never runs on a minion and has no billable compute time.
Validation rules
Section titled “Validation rules”- Exactly one Start node per top-level graph.
- Start must not have incoming edges.
- Start must not appear inside a fan-out template.