Events-based formulas are great for processing workflows based on notifications from a Poller or Webhook, but during development you may want to test the formula manually.
To do this test, you can use the minimum values required to trigger an Event-triggered formula with a payload including the 'events' object and your element instance ID. For example:
{
"events": [{
"objectType": "contacts",
"objectId": "876177",
"date": "2019-02-10T19:07:00Z",
"eventType": "CREATED",
"elementKey": "hubspot"
}],
"instance_id": 55555
}
You can use this payload to either POST /form