Runs a flow you built in Flow Builder and returns its result. See the Flow Builder guide for how flows, triggers and nodes work.

• Version. The flow's live version runs. You can't choose a version. If no version has been published yet, the latest saved version runs.
• API-trigger flows create a new application for every run. Send the trigger's inputs in params.
• Application-trigger flows run against an existing application. Send app_id (the application's numeric ID) or app_session (its session UUID). Any params you send are saved onto that application's data first.
• Environment. A live_ key runs the flow in Production. A test_ key runs it in Sandbox, so the flow must exist in Sandbox.
• Synchronous. The call returns when the flow ends. If the flow reaches a Delay or Wait for webhook node, the call returns right away with status set to scheduled and flow_resume_at set to when the delay ends or the wait expires. The rest of the flow runs in the background.

Check status, not just the HTTP code. A run that fails inside the flow still returns HTTP 200 with status set to failed.