What does a message look like?

Here is an example message. The top level properties are all mandatory, but the user may set anything inside the content property, as long as there is a type field which is a string between 3 and 64 characters long. (The type is up to 64 characters long so that it may be represented by a hash.)

{
  "previous": "%26AC+gU0t74jRGVeDY013cVghlZRc0nfUAnMnutGGHM=.sha256",
  "author": "@hxGxqPrplLjRG2vtjQL87abX4QKqeLgCwQpS730nNwE=.ed25519",
  "sequence": 216,
  "timestamp": 1442590513298,
  "hash": "sha256",
  "content": {
    "type": "vote",
    "vote": {
      "link": "%WbQ4dq0m/zu5jxll9zUbe0iGmDOajCx1ZkLKjZ80JvI=.sha256",
      "value": 1
    }
  },
  "signature": "Sjq1C3yiKdmi1TWvNqxIk1ZQBf4pPJYl0HHRDVf/xjm5tWJHBaW4kXo6mHPcUMbJYUtc03IvPwVqB+BMnBgmAQ==.sig.ed25519"
}

The previous is the hash of the message before this in the feed signed by author. author is the public key which signs this feed. The key pair for this feed may not be used for other feeds.