## Post

A post is a text-based message, for a public or private audience.
It can be a reply to other posts.

There's not a limit on the length of the text, but all Scuttlebot messages (including their headers) must be less than 8KB.

```js
{
  type: 'post',
  text: String,
  channel: String?,
  root: MsgLink?,
  branch: MsgLink? | MsgLinks?,
  recps: FeedLinks?,
  mentions: Links?
}
```

### Text

`text` is a markdown string that includes the body of the post.
See [SSB-Markdown](/apis/modules/ssb-markdown.html) for some Scuttlebot-specific markdown rules.

### Channel

`channel` is optionally used for categorization.
It's similar to subreddits or chat channels.

### Root and branch

`root` and `branch` are for replies.
`root` should point to the topmost message in the thread.
`branch` should point to the message or set of messages in the thread which is being replied to.

In the first reply of a thread, `root === branch`, and both should be included.
`root` and `branch` should only point to `type: post` messages.
If the post is about another message-type, use `mentions`.

### Mentions

`mentions` is a generic reference to other feeds, entities, blobs, or channels/hashtags.

 - User mentions: for when a user is referenced in the `text`.
 - Blob mentions: for when a file is referected in the `text`.
 - Message mentions: for when a message is referenced in the `text`.
 - Channel/hashtag mentions: for when a channel/hashtag is referenced in the `text`. Note: these are not returned in queries using the [`sbot.links`](/docs/advanced/links.html) method, but they are in queries using the [`ssb-backlinks`](https://www.npmjs.com/package/ssb-backlinks) plugin.

A link in `mentions` should be an object with property `link` set to a feed id, blob id, message id or hashtag. Additional properties may also be set, such as `name` for a name for the linked entity. For blob mentions, properties describing the file can be used, such as `size` (size in bytes), and `type` (mime-type).

### Recps

`recps` is a list of user-links specifying who the message is for.
This is typically used for encrypted messages, to specify who the message was encrypted for.

A link in `recps` should be either a feed id or an object with property `link` set to the feed id and optionally a `name` field for a name associated with the feed.