Webhook Registration and Triggers for Contact Note add

Please see my response to your other forum post Webhook for integration into apps The webhook is being registered, the action is subscriber_note not contact_note.

You can check what webhooks are registered by using the ActiveCampaign UI in settings → developer → manage webhooks. I would start here first before registering the webhooks programatically.

You should check there first to make sure the webhook exists, and is set for the action you want to listen for.

Then you can check this programmatically with the webhook_view API endpoint.