Common Properties

Properties that appear across multiple ActivityStreams types.

Identity

Property	Type	Description
@context	String/Array	JSON-LD context
id	URL	Globally unique identifier
type	String/Array	Object type(s)

{
  "@context": "https://www.w3.org/ns/activitystreams",
  "id": "https://example.com/notes/123",
  "type": "Note"
}

Naming

Property	Type	Description
name	String	Display name
nameMap	Object	Localized names
summary	String	Short description (HTML)
summaryMap	Object	Localized summaries

{
  "name": "My Post",
  "nameMap": {
    "en": "My Post",
    "es": "Mi Publicación"
  },
  "summary": "<p>A brief description</p>"
}

Content

Property	Type	Description
content	String	Main content (HTML)
contentMap	Object	Localized content
mediaType	String	MIME type of content
source	Object	Original source format

{
  "content": "<p>Hello <strong>world</strong>!</p>",
  "mediaType": "text/html",
  "source": {
    "content": "Hello **world**!",
    "mediaType": "text/markdown"
  }
}

Timestamps

Property	Type	Description
published	DateTime	Creation time
updated	DateTime	Last modification
startTime	DateTime	Event start
endTime	DateTime	Event end
duration	Duration	Time span

{
  "published": "2024-01-15T10:00:00Z",
  "updated": "2024-01-15T12:30:00Z"
}

Attribution

Property	Type	Description
attributedTo	Actor/URL	Creator/author
generator	Object	Creating application
audience	Actor/URL	Intended audience

{
  "attributedTo": "https://example.com/users/alice",
  "generator": {
    "type": "Application",
    "name": "My App"
  }
}

Addressing

Property	Type	Description
to	Array	Primary recipients
cc	Array	Secondary recipients
bto	Array	Private primary
bcc	Array	Private secondary

{
  "to": ["https://www.w3.org/ns/activitystreams#Public"],
  "cc": ["https://example.com/users/alice/followers"]
}

Special Addresses

Address	Meaning
https://www.w3.org/ns/activitystreams#Public	Public post
{actor}/followers	All followers

Media Attachments

Property	Type	Description
attachment	Array	Attached media
icon	Image	Thumbnail/avatar
image	Image	Representative image
preview	Link/Object	Preview version

{
  "attachment": [
    {
      "type": "Image",
      "mediaType": "image/png",
      "url": "https://example.com/image.png",
      "name": "Description for accessibility"
    }
  ]
}

Links and Relations

Property	Type	Description
url	URL/Link	Web page
href	URL	Link target
rel	String	Link relation
tag	Array	Hashtags/mentions
inReplyTo	URL	Reply target

{
  "tag": [
    {
      "type": "Hashtag",
      "name": "#fediverse",
      "href": "https://example.com/tags/fediverse"
    },
    {
      "type": "Mention",
      "name": "@bob@other.example",
      "href": "https://other.example/users/bob"
    }
  ]
}

Location

Property	Type	Description
location	Place	Geographic location
latitude	Float	Latitude
longitude	Float	Longitude
altitude	Float	Altitude
radius	Float	Accuracy radius

{
  "location": {
    "type": "Place",
    "name": "San Francisco",
    "latitude": 37.7749,
    "longitude": -122.4194
  }
}

See Also

• Object Properties
• Activity Properties
• Actor Properties