{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://api-evangelist.github.io/activitypub/json-schema/activitypub-activity-schema.json",
  "title": "ActivityPub Activity",
  "description": "JSON Schema for ActivityPub Activity objects as defined by https://www.w3.org/TR/activitypub/#activities and https://www.w3.org/TR/activitystreams-vocabulary/#activity-types",
  "type": "object",
  "required": ["@context", "type", "actor"],
  "properties": {
    "@context": {
      "description": "ActivityStreams 2.0 JSON-LD context",
      "oneOf": [
        {
          "type": "string",
          "const": "https://www.w3.org/ns/activitystreams"
        },
        {
          "type": "array",
          "items": {
            "oneOf": [
              { "type": "string" },
              { "type": "object" }
            ]
          }
        }
      ]
    },
    "id": {
      "type": "string",
      "format": "uri",
      "description": "Globally unique IRI of the activity (assigned by the server on publish)"
    },
    "type": {
      "type": "string",
      "enum": [
        "Accept",
        "Add",
        "Announce",
        "Arrive",
        "Block",
        "Create",
        "Delete",
        "Dislike",
        "Flag",
        "Follow",
        "Ignore",
        "Invite",
        "Join",
        "Leave",
        "Like",
        "Listen",
        "Move",
        "Offer",
        "Question",
        "Read",
        "Reject",
        "Remove",
        "TentativeAccept",
        "TentativeReject",
        "Travel",
        "Undo",
        "Update",
        "View"
      ],
      "description": "The activity type"
    },
    "actor": {
      "description": "The actor performing the activity — IRI or embedded Actor object",
      "oneOf": [
        { "type": "string", "format": "uri" },
        { "$ref": "#/$defs/ActorRef" }
      ]
    },
    "object": {
      "description": "The object on which the activity is performed",
      "oneOf": [
        { "type": "string", "format": "uri" },
        { "$ref": "#/$defs/ObjectOrActivity" }
      ]
    },
    "target": {
      "description": "The indirect target or destination of the activity",
      "oneOf": [
        { "type": "string", "format": "uri" },
        { "$ref": "#/$defs/ObjectOrActivity" }
      ]
    },
    "result": {
      "description": "Describes the result of the activity",
      "oneOf": [
        { "type": "string", "format": "uri" },
        { "$ref": "#/$defs/ObjectOrActivity" }
      ]
    },
    "origin": {
      "description": "The source from which the object originated (e.g., for Move)",
      "oneOf": [
        { "type": "string", "format": "uri" },
        { "$ref": "#/$defs/ObjectOrActivity" }
      ]
    },
    "instrument": {
      "description": "Tool or instrument used to perform the activity",
      "oneOf": [
        { "type": "string", "format": "uri" },
        { "$ref": "#/$defs/ObjectOrActivity" }
      ]
    },
    "to": {
      "description": "Primary audience — use https://www.w3.org/ns/activitystreams#Public for public posts",
      "oneOf": [
        { "type": "string", "format": "uri" },
        {
          "type": "array",
          "items": { "type": "string", "format": "uri" }
        }
      ]
    },
    "cc": {
      "description": "Secondary (carbon copy) audience",
      "oneOf": [
        { "type": "string", "format": "uri" },
        {
          "type": "array",
          "items": { "type": "string", "format": "uri" }
        }
      ]
    },
    "bto": {
      "description": "Private primary audience — MUST be stripped before delivery",
      "oneOf": [
        { "type": "string", "format": "uri" },
        {
          "type": "array",
          "items": { "type": "string", "format": "uri" }
        }
      ]
    },
    "bcc": {
      "description": "Private secondary audience — MUST be stripped before delivery",
      "oneOf": [
        { "type": "string", "format": "uri" },
        {
          "type": "array",
          "items": { "type": "string", "format": "uri" }
        }
      ]
    },
    "audience": {
      "description": "Additional audience designation",
      "oneOf": [
        { "type": "string", "format": "uri" },
        {
          "type": "array",
          "items": { "type": "string", "format": "uri" }
        }
      ]
    },
    "published": {
      "type": "string",
      "format": "date-time",
      "description": "When the activity occurred or was published"
    },
    "summary": {
      "type": "string",
      "description": "Short description or content warning"
    },
    "oneOf": {
      "type": "array",
      "description": "Single-answer poll options (Question only)",
      "items": { "$ref": "#/$defs/ObjectOrActivity" }
    },
    "anyOf": {
      "type": "array",
      "description": "Multiple-answer poll options (Question only)",
      "items": { "$ref": "#/$defs/ObjectOrActivity" }
    },
    "closed": {
      "description": "When or whether a Question is closed",
      "oneOf": [
        { "type": "string", "format": "date-time" },
        { "type": "boolean" },
        { "type": "string", "format": "uri" }
      ]
    }
  },
  "additionalProperties": true,
  "$defs": {
    "ActorRef": {
      "type": "object",
      "description": "An embedded actor object reference",
      "properties": {
        "id": { "type": "string", "format": "uri" },
        "type": {
          "type": "string",
          "enum": ["Person", "Application", "Group", "Organization", "Service"]
        },
        "name": { "type": "string" },
        "preferredUsername": { "type": "string" },
        "inbox": { "type": "string", "format": "uri" },
        "outbox": { "type": "string", "format": "uri" }
      }
    },
    "ObjectOrActivity": {
      "type": "object",
      "description": "An embedded ActivityStreams Object or Activity",
      "properties": {
        "id": { "type": "string", "format": "uri" },
        "type": { "type": "string" },
        "name": { "type": "string" },
        "content": { "type": "string" },
        "summary": { "type": "string" },
        "url": {
          "oneOf": [
            { "type": "string", "format": "uri" },
            { "type": "array", "items": { "type": "string", "format": "uri" } }
          ]
        },
        "attributedTo": {
          "oneOf": [
            { "type": "string", "format": "uri" },
            { "type": "array", "items": { "type": "string", "format": "uri" } }
          ]
        },
        "published": { "type": "string", "format": "date-time" },
        "to": {
          "oneOf": [
            { "type": "string", "format": "uri" },
            { "type": "array", "items": { "type": "string", "format": "uri" } }
          ]
        },
        "cc": {
          "oneOf": [
            { "type": "string", "format": "uri" },
            { "type": "array", "items": { "type": "string", "format": "uri" } }
          ]
        },
        "inReplyTo": {
          "oneOf": [
            { "type": "string", "format": "uri" },
            { "type": "array", "items": { "type": "string", "format": "uri" } }
          ]
        },
        "tag": {
          "type": "array",
          "items": { "type": "object" }
        },
        "attachment": {
          "type": "array",
          "items": { "type": "object" }
        },
        "sensitive": { "type": "boolean" },
        "mediaType": { "type": "string" },
        "formerType": { "type": "string" },
        "deleted": { "type": "string", "format": "date-time" }
      },
      "additionalProperties": true
    }
  },
  "examples": [
    {
      "@context": "https://www.w3.org/ns/activitystreams",
      "type": "Create",
      "actor": "https://social.example/users/alyssa",
      "to": ["https://www.w3.org/ns/activitystreams#Public"],
      "cc": ["https://social.example/users/alyssa/followers"],
      "object": {
        "@context": "https://www.w3.org/ns/activitystreams",
        "type": "Note",
        "content": "Say, did you finish reading that book I lent you?",
        "to": ["https://www.w3.org/ns/activitystreams#Public"],
        "cc": ["https://social.example/users/alyssa/followers"],
        "attributedTo": "https://social.example/users/alyssa",
        "published": "2015-01-21T20:04:00Z"
      }
    },
    {
      "@context": "https://www.w3.org/ns/activitystreams",
      "type": "Follow",
      "actor": "https://social.example/users/alyssa",
      "object": "https://remote.example/users/ben"
    },
    {
      "@context": "https://www.w3.org/ns/activitystreams",
      "type": "Like",
      "actor": "https://social.example/users/alyssa",
      "object": "https://remote.example/notes/12345"
    },
    {
      "@context": "https://www.w3.org/ns/activitystreams",
      "type": "Undo",
      "actor": "https://social.example/users/alyssa",
      "object": {
        "type": "Follow",
        "actor": "https://social.example/users/alyssa",
        "object": "https://remote.example/users/ben"
      }
    },
    {
      "@context": "https://www.w3.org/ns/activitystreams",
      "type": "Announce",
      "actor": "https://social.example/users/alyssa",
      "to": ["https://www.w3.org/ns/activitystreams#Public"],
      "object": "https://remote.example/notes/67890"
    }
  ]
}