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Verified against PieFed 1.8.5 (live JSON from piefed.social), FEDERATION.md, docs/activitypub_examples, app/activitypub/routes.py (main), Codeberg API on 2026-10-15.

PieFed

PieFed is a link aggregator for the Fediverse, similar to Reddit, written in Python. It federates with Lemmy and Mbin using the same FEP-1b12 group model.

Overview​

PropertyValue
LanguagePython (Flask)
DatabasePostgreSQL
LicenseAGPL-3.0
Repositorycodeberg.org/rimu/pyfedi
Documentationjoin.piefed.social/docs, FEDERATION.md
Latest releasev1.8.5 (2026-10-15; releases are frequent)

ActivityPub Implementation​

Per FEDERATION.md: communities are Group actors, users are Person actors, and posts are Page, Article, Link, Note or Question objects. Supported FEPs include 1b12 (groups), 7888 (context), c0e0 (emoji reactions), 3b86 (Activity Intents), 2677 (application actor), 5feb (search consent) and 2345 (fediverse:creator). PieFed's ActivityPub examples show full JSON for communities, users and each post type.

Group (Community)​

Trimmed from piefed.social:

{
  "type": "Group",
  "id": "https://piefed.social/c/piefed_meta",
  "preferredUsername": "piefed_meta",
  "name": "PieFed Meta",
  "attributedTo": "https://piefed.social/c/piefed_meta/moderators",
  "moderators": "https://piefed.social/c/piefed_meta/moderators",
  "featured": "https://piefed.social/c/piefed_meta/featured",
  "postingRestrictedToMods": false,
  "inbox": "https://piefed.social/c/piefed_meta/inbox",
  "followers": "https://piefed.social/c/piefed_meta/followers",
  "outbox": "https://piefed.social/c/piefed_meta/outbox"
}

As with Lemmy, name is the display title and moderators are in a collection (published both as attributedTo and moderators).

Page (Post)​

Trimmed from piefed.social; a link post carries its link as an attachment of type Link:

{
  "type": "Page",
  "id": "https://piefed.social/post/123",
  "attributedTo": "https://piefed.social/u/alice",
  "audience": "https://piefed.social/c/piefed_meta",
  "name": "Reducing PieFed storage usage",
  "content": "<p>…</p>",
  "contentMap": { "en": "<p>…</p>" },
  "mediaType": "text/html",
  "attachment": [{ "type": "Link", "href": "https://join.piefed.social/2026/10/11/reducing-piefed-storage-usage/" }],
  "language": { "identifier": "en", "name": "English" },
  "commentsEnabled": true,
  "stickied": true,
  "sensitive": false,
  "context": "…",
  "interactionPolicy": { "…": "…" }
}

Unlike Lemmy 0.19, PieFed still publishes commentsEnabled and stickied on posts.

Supported Activities​

Inbound handling in app/activitypub/routes.py covers Create, Update, Delete, Undo, Follow, Accept, Reject, Announce (communities re-broadcast activities, as in Lemmy), Like, Dislike, EmojiReact, Add, Remove, Lock, Block, Flag, Move, QuoteRequest, and PieFed-specific PollVote and ChooseAnswer.

Community Federation​

┌─────────────────┐                  ┌─────────────────┐
│  piefed.social  │◄──── Follow ─────│   lemmy.world   │
│ /c/programming  │                  │  (subscriber)   │
└────────┬────────┘                  └────────▲────────┘
         │                                    │
         └──── Announce(Create(Page)) ────────┘

API Endpoints​

GET /u/{username}       # Person
GET /c/{community}      # Group
GET /post/{id}          # Page and other post types
GET /comment/{id}       # Note
GET /c/{community}/outbox
GET /c/{community}/followers
GET /c/{community}/moderators
GET /c/{community}/featured

Voting​

Upvotes are Like and downvotes Dislike, as in Lemmy; Mastodon only understands Like. PieFed also accepts EmojiReact (FEP-c0e0).

See Also​