Skip to main content

Developer Resources

A comprehensive collection of libraries, tools, and resources for building ActivityPub and Fediverse applications.

Libraries by Language​

JavaScript / TypeScript​

LibraryDescriptionLicense
FedifyFull ActivityPub server frameworkMIT
ActivityPub ExpressExpress.js middleware for ActivityPub (unmaintained)MIT
express-activitypubSimple reference implementationMIT
activitystreams-2ActivityStreams 2.0 libraryApache-2.0
http-signatureHTTP Signatures implementationMIT
one-page-pubMinimal ActivityPub serverApache-2.0
// Example: Using Fedify
import { createFederation } from '@fedify/fedify';

const federation = createFederation({
  kv: new DenoKvStore(await Deno.openKv()),
});

federation.setActorDispatcher('/users/{handle}', async (ctx, handle) => {
  // Return actor object
});

Python​

LibraryDescriptionLicense
federationMulti-protocol social web libraryBSD-3
little-boxesMinimal ActivityPub frameworkISC
bovineFediverse application libraryMIT
pyfedType-safe ActivityPub libraryMIT
TakahēMulti-domain AP serverBSD-3
# Example: Using federation library
from federation.entities import base
from federation.outbound import handle_create

entity = base.Post(
    raw_content="Hello from Python!",
    id="https://example.com/posts/1"
)

Rust​

LibraryDescriptionLicense
activitypub-federationHigh-level AP framework (from Lemmy)AGPL-3.0
activitystreamsTraits and types for AS/APGPL-3.0
megalodon-rsMastodon/Pleroma API clientApache-2.0
// Example: Using activitypub-federation
use activitypub_federation::config::FederationConfig;

let config = FederationConfig::builder()
    .domain("example.com")
    .app_data(data)
    .build()?;

Go​

LibraryDescriptionLicense
go-fed/activityFull AS/AP implementationBSD-3
astreamsActivityStreams 2.0 libraryAGPL-3.0
HannibalActivityPub libraryApache-2.0
go-activitypubAP service implementationISC
// Example: Using go-fed/activity
import "github.com/go-fed/activity/streams"

note := streams.NewActivityStreamsNote()
note.GetActivityStreamsContent().Set(/* ... */)

PHP​

LibraryDescriptionLicense
ActivityPub-PHPActivityPub implementationMIT
FediTextText processing for FediverseMIT

Ruby​

LibraryDescriptionLicense
activitypubReference (Mastodon codebase)AGPL-3.0

Elixir​

LibraryDescriptionLicense
activity_pubActivityPub libraryAGPL-3.0
PleromaFull implementation referenceAGPL-3.0

Tools​

Testing & Debugging​

ToolDescription
activitypub-testsuiteW3C conformance tests
FediDBFediverse network statistics
Fediverse ObserverInstance monitoring

Development Utilities​

ToolDescription
HTTP Signature TesterVerify signature implementation
JSON-LD PlaygroundTest JSON-LD processing
WebFinger TesterTest WebFinger discovery

Instance Management​

ToolDescription
FediblockModeration blocklists
The FederationNetwork statistics

Reference Implementations​

Full Servers​

┌────────────────────────────────────────────────────────────┐
│              REFERENCE IMPLEMENTATIONS                     │
├────────────────────────────────────────────────────────────┤
│                                                            │
│  Microblogging                                             │
│  ├── Mastodon (Ruby)    - mastodon/mastodon               │
│  ├── Pleroma (Elixir)   - pleroma/pleroma                 │
│  └── Misskey (TS)       - misskey-dev/misskey             │
│                                                            │
│  Link Aggregation                                          │
│  └── Lemmy (Rust)       - LemmyNet/lemmy                  │
│                                                            │
│  Photo Sharing                                             │
│  └── Pixelfed (PHP)     - pixelfed/pixelfed               │
│                                                            │
│  Video                                                     │
│  └── PeerTube (TS)      - Chocobozzz/PeerTube             │
│                                                            │
│  Blogging                                                  │
│  ├── WriteFreely (Go)   - writefreely/writefreely         │
│  └── Plume (Rust)       - Plume-org/Plume                 │
│                                                            │
└────────────────────────────────────────────────────────────┘

Minimal Examples​

ProjectLanguagePurpose
one-page-pubNode.jsSingle-file AP server
express-activitypubNode.jsReference implementation
microblog.pubPythonSingle-user server

Specifications​

Core Standards​

SpecificationURL
ActivityPubw3.org/TR/activitypub
ActivityStreams 2.0 Corew3.org/TR/activitystreams-core
ActivityStreams 2.0 Vocabularyw3.org/TR/activitystreams-vocabulary
JSON-LDw3.org/TR/json-ld
WebFingerRFC 7033

De Facto Standards​

SpecificationDocumentation
HTTP Signaturesdocs.joinmastodon.org/spec/security
NodeInfonodeinfo.diaspora.software
Mastodon Extensionsdocs.joinmastodon.org

Learning Resources​

Tutorials​

ResourceDescription
ActivityPub RocksOfficial resource site
How to Implement ActivityPubMastodon blog tutorial
Building an ActivityPub ServerSocialHub discussion

Diagrams & Visual References​

ResourceDescription
boyter/activitypubSequence diagrams for common flows: Follow, Create, Delete, Announce, Move, WebFinger — a "clean room" implementation reference (MIT)

Video Content​

ResourceDescription
FediForum RecordingsPast session recordings
PeerTube InstancesVarious developer tutorials

Books​

ResourceDescription
Move Slowly and Build BridgesRobert W. Gehl's book on Mastodon

Community Resources​

Forums & Discussion​

ResourceDescription
SocialHubDeveloper community forum
Lemmy CommunitiesFediverse discussions
Matrix/DiscordReal-time chat

News & Updates​

ResourceDescription
We DistributeFediverse news
Fediverse ReportWeekly updates
This Week in MatrixRelated protocol news

Curated Lists​

ResourceURL
Delightful AP Developmentcodeberg.org/fediverse/delightful-activitypub-development
Awesome ActivityPubgithub.com/BasixKOR/awesome-activitypub
Fediverse.Party Toolsfediverse.party/en/tools

API Documentation​

Platform APIs​

PlatformDocumentation
Mastodondocs.joinmastodon.org/api
Lemmyjoin-lemmy.org/docs
Pixelfeddocs.pixelfed.org
PeerTubedocs.joinpeertube.org/api-rest-reference

Library Documentation​

LibraryDocumentation
Fedifyfedify.dev/docs
go-fed/activitygo-fed.org
activitypub-federation-rustdocs.rs/activitypub_federation

Quick Reference​

Essential URLs​

┌────────────────────────────────────────────────────────────┐
│                  ESSENTIAL URLS                            │
├────────────────────────────────────────────────────────────┤
│                                                            │
│  Specifications                                            │
│  ├── w3.org/TR/activitypub                                │
│  ├── w3.org/TR/activitystreams-core                       │
│  └── w3.org/TR/activitystreams-vocabulary                 │
│                                                            │
│  Community                                                 │
│  ├── socialhub.activitypub.rocks                          │
│  ├── activitypub.rocks                                    │
│  └── codeberg.org/fediverse/fep                           │
│                                                            │
│  Tools                                                     │
│  ├── json-ld.org/playground                               │
│  ├── webfinger.net/lookup                                 │
│  └── fedidb.org                                           │
│                                                            │
└────────────────────────────────────────────────────────────┘

Common Namespaces​

{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://w3id.org/security/v1",
    {
      "toot": "http://joinmastodon.org/ns#",
      "schema": "http://schema.org#",
      "PropertyValue": "schema:PropertyValue",
      "value": "schema:value"
    }
  ]
}

Getting Help​

Where to Ask Questions​

  1. SocialHub Forum - Best for implementation questions
  2. Matrix Rooms - Real-time help
  3. GitHub Issues - Library-specific questions
  4. Stack Overflow - Tag with activitypub

Debugging Tips​

// Log incoming activities
app.post('/inbox', (req, res) => {
  console.log('Received activity:', JSON.stringify(req.body, null, 2));
  // Process activity...
});

// Verify HTTP signatures
const isValid = await verifySignature(req);
console.log('Signature valid:', isValid);

Next Steps​