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ActivityPub

ActivityPub is a W3C Recommendation that defines a decentralized social networking protocol and REST API standard for federated social interactions. It provides both a client-to-server API for creating and managing social content and a server-to-server federation protocol for distributing activities across instances. Built on ActivityStreams 2.0 and JSON-LD, it powers the Fediverse — including Mastodon, Pixelfed, PeerTube, and hundreds of other platforms — enabling interoperable social networking across independently operated servers.

8 APIs 0 Features
Open StandardSocial NetworksFederationFediverseW3C

APIs

ActivityPub Actors API

Actors are the primary objects in ActivityPub that represent entities capable of performing activities. Each actor has a unique IRI and exposes properties such as inbox, outbox,...

ActivityPub Inbox API

The inbox is an OrderedCollection endpoint on each actor that receives activities delivered by remote servers. Servers POST activities to an actor's inbox to federate content. T...

ActivityPub Outbox API

The outbox is an OrderedCollection endpoint that stores activities published by an actor. Clients POST activities to an actor's outbox to create, update, delete, follow, like, a...

ActivityPub Followers and Following API

Actors expose followers and following as OrderedCollection or Collection endpoints. These endpoints enumerate the social graph connections for an actor. The Follow activity post...

ActivityPub Liked Collection API

The liked collection is an optional OrderedCollection endpoint on an actor listing all objects the actor has liked. Posting a Like activity to the actor's outbox adds the refere...

ActivityPub Object and Activity Delivery API

ActivityPub defines a server-to-server federation protocol for delivering activities between instances. Servers dereference actor inboxes from WebFinger or direct URLs, then HTT...

ActivityPub WebFinger Discovery API

ActivityPub implementations commonly use WebFinger (RFC 7033) for actor discovery. A GET request to /.well-known/webfinger?resource=acct:[email protected] returns a JSON Resource...

ActivityPub NodeInfo API

NodeInfo is a complementary protocol used by ActivityPub servers to expose server capability metadata at /.well-known/nodeinfo. It describes the software name, version, supporte...

Semantic Vocabularies

Activitypub Context

59 classes · 73 properties

JSON-LD

Resources

🔗
Website
Website
🔗
Documentation
Documentation
🔗
Specification
Specification
🚀
GettingStarted
GettingStarted
🔑
Authentication
Authentication
🔗
Security
Security
👥
GitHubOrganization
GitHubOrganization
👥
GitHubRepository
GitHubRepository
🔗
Forum
Forum
📄
Changelog
Changelog
🔗
Vocabulary
Vocabulary
🔗
JSONSchema
JSONSchema
🔗
RateLimits
RateLimits
🔗
Plans
Plans
🔗
FinOps
FinOps

Sources

apis.yml Raw ↑ 
aid: activitypub
url: https://raw.githubusercontent.com/api-evangelist/activitypub/refs/heads/main/apis.yml
apis:
  - aid: activitypub:activitypub-actors-api
    name: ActivityPub Actors API
    tags:
      - Actors
      - Profiles
      - Social Networks
    properties:
      - url: https://www.w3.org/TR/activitypub/#actors
        type: Documentation
      - url: https://www.w3.org/TR/activitypub/#actor-objects
        type: APIReference
    description: >-
      Actors are the primary objects in ActivityPub that represent entities capable of performing
      activities. Each actor has a unique IRI and exposes properties such as inbox, outbox,
      followers, following, and liked collections. Actor objects are retrieved via HTTP GET and
      served as JSON-LD using the ActivityStreams 2.0 vocabulary.
  - aid: activitypub:activitypub-inbox-api
    name: ActivityPub Inbox API
    tags:
      - Inbox
      - Messages
      - Delivery
      - Social Networks
    properties:
      - url: https://www.w3.org/TR/activitypub/#inbox
        type: Documentation
      - url: https://www.w3.org/TR/activitypub/#server-to-server-interactions
        type: APIReference
    description: >-
      The inbox is an OrderedCollection endpoint on each actor that receives activities delivered
      by remote servers. Servers POST activities to an actor's inbox to federate content. The
      inbox also supports GET for authorized clients to retrieve received activities. ActivityPub
      uses HTTP Signatures for server-to-server authentication when delivering to inboxes.
  - aid: activitypub:activitypub-outbox-api
    name: ActivityPub Outbox API
    tags:
      - Outbox
      - Publishing
      - Activities
      - Social Networks
    properties:
      - url: https://www.w3.org/TR/activitypub/#outbox
        type: Documentation
      - url: https://www.w3.org/TR/activitypub/#client-to-server-interactions
        type: APIReference
    description: >-
      The outbox is an OrderedCollection endpoint that stores activities published by an actor.
      Clients POST activities to an actor's outbox to create, update, delete, follow, like, and
      perform other social interactions. The server then federates these activities to the
      appropriate recipients. The outbox also supports GET for reading published activities.
  - aid: activitypub:activitypub-followers-following-api
    name: ActivityPub Followers and Following API
    tags:
      - Followers
      - Following
      - Social Graph
      - Social Networks
    properties:
      - url: https://www.w3.org/TR/activitypub/#followers
        type: Documentation
      - url: https://www.w3.org/TR/activitypub/#following
        type: APIReference
    description: >-
      Actors expose followers and following as OrderedCollection or Collection endpoints.
      These endpoints enumerate the social graph connections for an actor. The Follow activity
      posted to the outbox initiates a follow relationship; the target actor can accept or reject
      via Accept or Reject activities. These collections are pageable via OrderedCollectionPage.
  - aid: activitypub:activitypub-liked-api
    name: ActivityPub Liked Collection API
    tags:
      - Liked
      - Reactions
      - Activities
      - Social Networks
    properties:
      - url: https://www.w3.org/TR/activitypub/#liked
        type: Documentation
    description: >-
      The liked collection is an optional OrderedCollection endpoint on an actor listing
      all objects the actor has liked. Posting a Like activity to the actor's outbox adds
      the referenced object to this collection. It is publicly readable and supports pagination
      through the standard ActivityStreams 2.0 collection paging mechanism.
  - aid: activitypub:activitypub-object-delivery-api
    name: ActivityPub Object and Activity Delivery API
    tags:
      - Activities
      - Objects
      - Delivery
      - Federation
      - Social Networks
    properties:
      - url: https://www.w3.org/TR/activitypub/#delivery
        type: Documentation
      - url: https://www.w3.org/TR/activitypub/#activity-types
        type: APIReference
    description: >-
      ActivityPub defines a server-to-server federation protocol for delivering activities between
      instances. Servers dereference actor inboxes from WebFinger or direct URLs, then HTTP POST
      signed Activity objects (Create, Update, Delete, Announce, Follow, Accept, Reject, Undo,
      Block, etc.) using JSON-LD with the ActivityStreams context. Delivery handles addressing
      via to, cc, bcc, and audience fields.
  - aid: activitypub:activitypub-webfinger-api
    name: ActivityPub WebFinger Discovery API
    tags:
      - WebFinger
      - Discovery
      - Identity
      - Social Networks
    properties:
      - url: https://www.w3.org/TR/activitypub/#security-considerations
        type: Documentation
      - url: https://webfinger.net/
        type: APIReference
      - url: https://www.rfc-editor.org/rfc/rfc7033
        type: Documentation
    description: >-
      ActivityPub implementations commonly use WebFinger (RFC 7033) for actor discovery.
      A GET request to /.well-known/webfinger?resource=acct:[email protected] returns a
      JSON Resource Descriptor (JRD) linking to the actor's canonical ActivityPub profile URL.
      WebFinger enables cross-instance lookup of actors using familiar user@domain addressing
      across the Fediverse.
  - aid: activitypub:activitypub-nodeinfo-api
    name: ActivityPub NodeInfo API
    tags:
      - NodeInfo
      - Discovery
      - Server Metadata
      - Social Networks
    properties:
      - url: https://nodeinfo.diaspora.software/
        type: Documentation
      - url: https://www.w3.org/TR/activitypub/#actor-objects
        type: APIReference
    description: >-
      NodeInfo is a complementary protocol used by ActivityPub servers to expose server
      capability metadata at /.well-known/nodeinfo. It describes the software name, version,
      supported protocols, usage statistics, and open registration status, enabling clients
      and crawlers to understand server capabilities without inspecting individual actors.
name: ActivityPub
tags:
  - Open Standard
  - Social Networks
  - Federation
  - Fediverse
  - W3C
type: Index
image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
access: 3rd-Party
created: '2026-06-13'
modified: '2026-06-13'
position: Consumer
description: >-
  ActivityPub is a W3C Recommendation that defines a decentralized social networking protocol
  and REST API standard for federated social interactions. It provides both a client-to-server
  API for creating and managing social content and a server-to-server federation protocol for
  distributing activities across instances. Built on ActivityStreams 2.0 and JSON-LD, it powers
  the Fediverse — including Mastodon, Pixelfed, PeerTube, and hundreds of other platforms —
  enabling interoperable social networking across independently operated servers.
maintainers:
  - FN: Kin Lane
    email: [email protected]
  - FN: APIs.json
    email: [email protected]
specificationVersion: '0.19'
common:
  - type: Website
    url: https://activitypub.rocks/
  - type: Documentation
    url: https://www.w3.org/TR/activitypub/
  - type: Specification
    url: https://www.w3.org/TR/activitypub/
  - type: GettingStarted
    url: https://activitypub.rocks/
  - type: Authentication
    url: https://www.w3.org/TR/activitypub/#authorization
  - type: Security
    url: https://www.w3.org/TR/activitypub/#security-considerations
  - type: UseCases
    url: https://www.w3.org/TR/activitypub/#overview
  - type: GitHubOrganization
    url: https://github.com/w3c/activitypub
  - type: GitHubRepository
    url: https://github.com/w3c/activitypub
  - type: Forum
    url: https://socialhub.activitypub.rocks/
  - type: Changelog
    url: https://www.w3.org/TR/activitypub/#change-log
  - type: Vocabulary
    url: https://www.w3.org/TR/activitystreams-vocabulary/
  - type: JSONSchema
    url: https://www.w3.org/TR/activitystreams-core/
  - type: RateLimits
    url: rate-limits/activitypub-rate-limits.yml
  - type: Plans
    url: plans/activitypub-plans.yml
  - type: FinOps
    url: finops/activitypub-finops.yml