How do I format the contact 'note' field when added via API

I can use the contact/note/add api to add note comments to the contact record. And I have see other notes added by different integrations that have the ‘note’ field somewhat formated. But how do I format the note field data? If I use html it is stripped off. So there must be some other way of formating the note data.

I can see in V1 of the API that HTML will be stripped with the contact_note_add endpoint:

image

I’ve tried to add html to a note using the v3 API and it’s just being added as plain text.

I’m not sure of what voodoo is going on to allow HTML in notes otherwise, and I can’t see anything in AC’s docs.