curl --request POST \
  --url https://api.hubapi.com/integrations/v1/{application}-id/timeline/event-types

"\nExample POST URL:\nhttps://api.hubapi.com/integrations/v1/123/timeline/event-types?hapikey=xxxx-xxxx-xxxx-xxxx&userId=123456\n\nExample JSON to create a new event type, with header and detail templates:\n\n{\n  \"name\":\"New Event Type\",\n  \"applicationId\":\"123\",\n  \"objectType\":\"CONTACT\",\n  \"headerTemplate\":\"# Title for event {% raw %}{{id}}{% endraw %}\nThis is an event for {% raw %}{{objectType}}{% endraw %}\",\n  \"detailTemplate\":\"This event happened on {% raw %}{{#formatDate timestamp}}{{/formatDate}}{% endraw %}\"\n}\n\n\nThe response will contain all fields plus the generated ID. Example for this response would be:\n\n{\n  \"id\":261,\n  \"name\":\"Test Event Type\",\n  \"headerTemplate\":\"# Title for event {% raw %}{{id}}{% endraw %}\nThis is an event for {% raw %}{{objectType}}{% endraw %}\",\n  \"detailTemplate\":\"This event happened on {% raw %}{{#formatDate timestamp}}{{/formatDate}}{% endraw %}\",\n  \"applicationId\":123,\n  \"objectType\": \"CONTACT\"\n}"