create-message1.json

{
  "@context": "https://www.w3.org/ns/activitystreams",
  "type": "Create",
  "id": "https://social.example/alyssa/posts/a29a6843-9feb-4c74-a7f7-081b9c9201d3",
  "to": ["https://chatty.example/ben/"],
  "author": "https://social.example/alyssa/",
  "object": {
    "type": "Note",
    "id": "https://social.example/alyssa/posts/49e2d03d-b53a-4c4c-a95c-94a6abf45a19",
    "attributedTo": "https://social.example/alyssa/",
    "to": ["https://chatty.example/ben/"],
    "content": "Say, did you finish reading that book I lent you?"
  }
}