matrix-spec/event-schemas/core

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "definitions": {
    "event": {
      "type": "object",
      "properties": {
        "event_id": {
          "type": "string"
        },
        "user_id": {
          "type": "string"
        },
        "content": {
          "type": "object"
        },
        "type": {
          "type": "string"
        }
      },
      "required": ["event_id", "user_id", "content", "type"]
    },
    "room_event": {
        "type": "object",
        "allOf":[{
            "$ref": "#/definitions/event"
        }],
        "properties": {
            "room_id": {
                "type": "string"
            }
        },
        "required": ["room_id"]
    }
  }
}