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