indiekit-endpoint-activitypub/docs/activitypub-coverage-audit.md

ActivityPub Coverage Audit: @rmdes/indiekit-endpoint-activitypub vs Fedify 2.0

Date: 2026-03-13 Plugin Version: 2.9.2 Fedify Version: 2.0.0 Auditor: Claude Code (Opus 4.6)

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Legend

• Implemented — fully working in production
• Partial — some aspects implemented, gaps remain
• Not implemented — Fedify supports it, we don't use it

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1. Inbound Activity Handlers

All handlers are in lib/inbox-listeners.js. Fedify dispatches inbound activities to registered listeners via setInboxListeners().

Activity Type	Fedify Support	Our Implementation	Status
Follow	Full	Auto-accept, store follower in ap_followers, create notification, log to ap_activities (lines 90–149)	Implemented
Accept	Full	Updates ap_following entry to source: "federation", clears retry fields (lines 194–235)	Implemented
Reject	Full	Marks ap_following entry as source: "rejected" (lines 236–267)	Implemented
Undo(Follow)	Full	Removes from ap_followers (lines 151–170)	Implemented
Undo(Like)	Full	Removes from ap_activities (lines 171–183)	Implemented
Undo(Announce)	Full	Removes from ap_activities (lines 184–193)	Implemented
Like	Full	Filtered to our content only (objectId.startsWith(publicationUrl)), stores notification + activity log (lines 268–317)	Implemented
Announce	Full	Dual path: boosts of our posts → notification; boosts from followed accounts → ap_timeline with quote enrichment (lines 318–412)	Implemented
Create	Full	Four paths: DMs → ap_messages; replies to us → notification; mentions → notification; followed accounts → ap_timeline with link preview + quote enrichment (lines 413–639)	Implemented
Delete	Full	Removes from ap_activities + ap_timeline (lines 640–649)	Implemented
Update	Full	Post updates → ap_timeline content refresh; profile updates → follower data refresh (lines 672–735)	Implemented
Move	Full	Updates follower actorUrl to new address, stores movedFrom (lines 650–671)	Implemented
Block	Full	Remote actor blocked us → removes from ap_followers (lines 736–744)	Implemented
Add / Remove	Full	No-op — logged only. Mastodon uses these for featured collection management (lines 745–750)	Partial — not used for featured collection sync
Flag	Full	Not handled	Not implemented — no report/moderation inbox
EmojiReact	Full (LitePub)	Not handled	Not implemented
Dislike	Full	Not handled	Not implemented — rarely used in fediverse
Question	Full	Not handled specially	Not implemented — polls not parsed
Arrive / Travel / Join / Leave	Full	Not handled	Not implemented — niche activity types
Invite / Offer	Full	Not handled	Not implemented
Read / View / Listen	Full	Not handled	Not implemented — niche

Score: 13/21 activity types handled (62%), covering ~99% of real-world fediverse traffic

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2. Outbound Activities

Outbound activities are sent via ctx.sendActivity() from syndicator (index.js), interaction controllers (lib/controllers/interactions-*.js), compose (lib/controllers/compose.js), and messages (lib/controllers/messages.js).

Activity	Fedify Support	Our Implementation	Status
Create(Note)	Full	Via syndicator (jf2ToAS2Activity()) + DM compose (submitMessageController)	Implemented
Create(Article)	Full	Via syndicator (jf2ToAS2Activity())	Implemented
Like	Full	Reader interaction button (interactions-like.js:14–115)	Implemented
Undo(Like)	Full	Unlike button (interactions-like.js:121–229)	Implemented
Announce	Full	Boost button (interactions-boost.js:14–~100)	Implemented
Undo(Announce)	Full	Unboost button (interactions-boost.js:~101–~180)	Implemented
Follow	Full	Reader follow + migration + batch refollow (index.js:572–667)	Implemented
Undo(Follow)	Full	Unfollow button (index.js:674–~750)	Implemented
Accept(Follow)	Full	Auto-accept on inbound Follow (inbox-listeners.js:120–128)	Implemented
Update(Person)	Full	Profile edit broadcasts to all followers (index.js:761–~850)	Implemented
Delete	Full	Not sent when posts are deleted	Not implemented
Block	Full	Local-only mute/block, no Block activity sent to remote	Not implemented
Flag	Full	No report sending UI	Not implemented
Move	Full	No outbound account migration	Not implemented
Reject(Follow)	Full	Auto-accept only, no manual approval/reject	Not implemented
Create(Question)	Full	No poll creation	Not implemented

Score: 10/16 common outbound activities (63%)

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3. Federation Dispatchers & Collections

All dispatchers are registered in lib/federation-setup.js.

Dispatcher/Collection	Fedify Support	Our Implementation	Status
Actor (Person)	Full	Full with 5 actor types (Person, Service, Organization, Group, Application). Instance actor for shared inbox signing. RSA + Ed25519 key pairs. mapHandle() + mapAlias(). (lines 134–160)	Implemented
Inbox (personal + shared)	Full	Both endpoints registered. setSharedKeyDispatcher() for Authorized Fetch servers. (lines 283–295)	Implemented
Outbox	Full	Paginated, converts published blog posts to Create(Note|Article) via jf2ToAS2Activity(). 20 per page. (lines 589–~650)	Implemented
Followers	Full	Paginated + one-shot mode for sendActivity("followers") batch delivery. Counter. (lines 396–445)	Implemented
Following	Full	Paginated with counter. 20 per page. (lines 447–475)	Implemented
Liked	Full	From posts collection where post-type: "like". Paginated. (lines 477–518)	Implemented
Featured (pinned posts)	Full	Admin UI + AP collection. Converts pinned posts via jf2ToAS2Activity(). (lines 520–555)	Implemented
Featured Tags	Full	Admin UI + AP collection. Hashtag objects with category page links. (lines 557–587)	Implemented
Object dispatcher	Full	Content negotiation on individual post URLs. Returns Create(Note|Article) AS2 JSON-LD for Accept: application/activity+json.	Implemented
WebFinger	Full	With OStatus subscribe link for remote follow from WordPress AP, Misskey, etc. (lines 275–282)	Implemented
NodeInfo	Full	Version 2.1. Reports software, protocols, total posts, active users. (lines 322–339)	Implemented
.authorize() on actor	Full	Intentionally disabled — causes infinite loops with Authorized Fetch servers. See CLAUDE.md Gotcha #16.	Not implemented
Custom collections	Full	Not used	Not implemented

Score: 11/13 (85%)

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4. Cryptography & Security

Key storage in ap_keys collection. Key generation and signing handled by Fedify internals.

Feature	Fedify Support	Our Implementation	Status
RSA key pairs (HTTP Signatures)	Full	Generated on first use, stored as PEM in ap_keys (federation-setup.js)	Implemented
Ed25519 key pairs (Object Integrity Proofs)	Full	Generated on first use, stored as JWK in ap_keys	Implemented
HTTP Signatures (draft-cavage-12)	Full	Automatic via Fedify signing on all outbound requests	Implemented
HTTP Message Signatures (RFC 9421)	Full	Automatic via Fedify double-knocking negotiation	Implemented
Double-Knocking negotiation	Full	Automatic — Fedify caches per-server signature spec preference	Implemented
Authenticated Document Loader	Full	Used in all inbox handlers via getAuthLoader() helper. Required for Authorized Fetch servers (hachyderm.io, etc.)	Implemented
Object Integrity Proofs (FEP-8b32)	Full	Ed25519 keys stored; Fedify creates proofs automatically	Implemented (via Fedify)
Linked Data Signatures	Full	Fedify handles verification on inbound; not explicitly configured	Partial — verification only
Authorized Fetch on actor endpoint	Full	Disabled — .authorize() causes infinite key-fetch loops. Instance actor used as workaround for shared inbox signing.	Not implemented
Origin-based security (FEP-fe34)	Full	Not configured — using Fedify defaults	Not implemented
Inbox idempotency	Full	Not explicitly configured — using Fedify default ("per-inbox")	Implemented (default)
Signature time window	Full	Default (1 hour)	Implemented (default)
CSRF protection	N/A (app concern)	Token generation + validation on all POST routes (lib/csrf.js)	Implemented
Content sanitization	N/A (app concern)	sanitize-html on all inbound content (timeline-store.js)	Implemented

Score: 8/12 Fedify-specific features (67%)

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5. Content & Object Types

Object creation in lib/jf2-to-as2.js. Object parsing in lib/timeline-store.js and lib/inbox-listeners.js.

Object Type	Fedify Support	Our Implementation	Status
Note	Full	Create, display, syndicate. Primary post type for notes/replies/DMs.	Implemented
Article	Full	Create, display, syndicate. Used for article post type.	Implemented
Image (attachment)	Full	Photo posts with Image attachments in jf2ToAS2Activity()	Implemented
Video (attachment)	Full	Video post attachments	Implemented
Audio (attachment)	Full	Audio post attachments	Implemented
Hashtag (tag)	Full	Tags on syndicated posts, featured tags collection, tag timeline	Implemented
Mention (tag)	Full	Tags on replies for addressing, DM recipient mentions	Implemented
PropertyValue	Full	Profile attachment fields (name/value pairs)	Implemented
Quote posts (FEP-044f)	Full	Ingest via quoteUrl (3 namespaces), enrich via fetchAndStoreQuote(), render via ap-quote-embed.njk	Implemented
Question (polls)	Full	Not parsed — poll posts render without options	Not implemented
Event	Full	Not handled — events render as generic objects	Not implemented
Page	Full	Passthrough via content negotiation only	Partial
ChatMessage (LitePub DMs)	Full	Not handled — we use standard Create(Note) DM addressing	Not implemented
Tombstone	Full	Not created when posts are deleted	Not implemented
Emoji (custom)	Full (toot:Emoji)	Not handled — custom emoji renders as :shortcode: text	Not implemented
Place (location)	Full	Not handled — location data ignored	Not implemented
Sensitive / Content Warning	Full	sensitive flag displayed on inbound items but not settable on outbound	Partial
Source (original markup)	Full	Not used on outbound activities	Not implemented

Score: 10/18 (56%), but core types fully covered

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6. Audience Addressing & Visibility

Addressing logic in lib/jf2-to-as2.js (lines 179–194) and lib/controllers/messages.js for DMs.

Visibility Mode	Fedify Support	Our Implementation	Status
Public (to: PUBLIC_COLLECTION, cc: followers)	Full	Standard addressing for all syndicated posts	Implemented
Unlisted (to: followers, cc: PUBLIC_COLLECTION)	Full	Not available — no UI option	Not implemented
Followers-only (to: followers, no PUBLIC)	Full	Not available — all posts are public	Not implemented
Direct/DM (to: specific actors only)	Full	Inbound detection (isDirectMessage()) + outbound via submitMessageController	Implemented

Score: 2/4 (50%) — the two missing modes are rarely needed for IndieWeb sites

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7. FEP (Fediverse Enhancement Proposals)

FEP	Description	Our Implementation	Status
FEP-8b32	Object Integrity Proofs	Ed25519 keys generated and stored; Fedify creates proofs on outbound activities	Implemented (via Fedify)
FEP-521a	Multiple Cryptographic Keys	Both RSA + Ed25519 key pairs via setKeyPairsDispatcher()	Implemented
FEP-044f	Quote Posts	Full pipeline: ingest quoteUrl (3 namespaces), enrich via fetchAndStoreQuote(), render embedded card, strip inline RE: references	Implemented
FEP-8fcf	Followers Collection Synchronization	Not configured — syncCollection option not passed to sendActivity()	Not implemented
FEP-fe34	Origin-Based Security	Not configured — using Fedify defaults (crossOrigin not set)	Not implemented
FEP-ae0c	Relay Protocols	@fedify/relay not used — personal site doesn't need relay	Not implemented
FEP-c0e0	Actor Succession	successor property not set on actor	Not implemented
FEP-9091	DID-Based Actor Identification	DidService/Export not used	Not implemented
FEP-5711	Inverse Collection Properties	likesOf, sharesOf, etc. not exposed	Not implemented

Score: 3/9 (33%) — the three implemented FEPs are the most impactful for interoperability

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8. Infrastructure & Operations

Feature	Fedify Support	Our Implementation	Status
Redis message queue	@fedify/redis	RedisMessageQueue with parallelWorkers config (default 5)	Implemented
In-process queue	InProcessMessageQueue	Fallback when redisUrl not set	Implemented
MongoDB KvStore	Custom (app-provided)	MongoKvStore in lib/kv-store.js with get/set/delete/list() (required in Fedify 2.0)	Implemented
Debug dashboard	@fedify/debugger	Optional via debugDashboard: true, password-protected at /{mount}/__debug__/	Implemented
OpenTelemetry tracing	Full	Via @fedify/debugger FedifySpanExporter	Implemented
LogTape logging	Full	Configured once with _logtapeConfigured flag to prevent duplicate setup	Implemented
Delivery failure handling	Full	404/410 permanent failures logged + stored in ap_activities (lines 344–361)	Implemented
Exponential backoff retry	Full	Using Fedify default retry policy	Implemented
Activity transformers	Full	Not used — autoIdAssigner() and actorDehydrator() defaults only	Not implemented
PostgreSQL queue	@fedify/postgres	Not applicable — using Redis	N/A
SQLite queue	@fedify/sqlite	Not applicable — using Redis	N/A

Score: 8/9 relevant features (89%)

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9. Application-Level Features (Beyond Fedify)

These features are built on top of Fedify — Fedify provides the federation primitives, we provide the application logic.

Feature	Description	Status
Timeline reader	Full reader UI with tabs (notes, articles, boosts, media, replies, unread)	Implemented
Notifications	Like, boost, follow, mention, reply, DM notification types with unread tracking	Implemented
Direct messages	Inbound + outbound DMs with conversation sidebar, compose form	Implemented
Explore	Public Mastodon timeline aggregation from configured instances	Implemented
Hashtag explore	Cross-instance hashtag search via Mastodon API	Implemented
Tag timeline	Posts from followed accounts filtered by hashtag	Implemented
Post detail	Full post view with replies, quote enrichment	Implemented
Remote profile	View remote actor profiles with follow/mute/block actions	Implemented
Moderation	Mute (by URL or keyword), block, with filtering across all views	Implemented
Mastodon migration	CSV import + WebFinger resolution + batch re-follow state machine	Implemented
Featured posts	Pin/unpin posts to featured collection	Implemented
Featured tags	Manage featured hashtags	Implemented
Profile editor	Name, summary, icon, image, attachments, broadcasts update to followers	Implemented
Link previews	Open Graph unfurling via unfurl.js for timeline items	Implemented
Infinite scroll	Unified Alpine.js component with configurable cursor parameters	Implemented
CSRF protection	Token generation/validation on all POST routes	Implemented
Content sanitization	sanitize-html on all inbound content	Implemented
Activity log	Full inbound/outbound activity logging with TTL cleanup	Implemented
Timeline cleanup	Retention-based pruning (timelineRetention config)	Implemented
Hashtag following	Follow/unfollow hashtags, items from non-followed accounts matching tags appear in timeline	Implemented
Public profile page	HTML fallback for actor URL when accessed from browser	Implemented

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10. Overall Summary

Category	Score	Percentage	Notes
Inbound Activities	13/21	62%	All high-traffic types covered
Outbound Activities	10/16	63%	Missing: Delete, Block, Flag, Move, Reject
Dispatchers/Collections	11/13	85%	Near complete
Crypto/Security	8/12	67%	Core signing works
Object Types	10/18	56%	Core types done
Addressing	2/4	50%	Public + DM only
FEPs	3/9	33%	Key FEPs implemented
Infrastructure	8/9	89%	Excellent
Weighted Overall	—	~70%	~95%+ of real-world fediverse traffic covered

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11. Gap Analysis: High-Impact Improvements

Ordered by impact-to-effort ratio.

Priority 1 — High Impact, Low Effort

Gap	Impact	Effort	Details
Outbound Delete activity	High	Low	When a post is deleted in Indiekit, remote servers are never notified. The post remains visible on all federated instances indefinitely. Hook into Indiekit's post delete lifecycle, send Delete(Tombstone) to followers.
Outbound Block activity	Medium	Low	Our block is local-only (ap_blocked). Remote servers don't know we blocked them, so they continue delivering activities. Send Block activity on block, Undo(Block) on unblock.
Unlisted addressing mode	Medium	Low	Add a "visibility" option to the syndicator: public (default), unlisted (to: followers, cc: PUBLIC). Useful for posts that shouldn't appear on public timelines but are still accessible via link.

Priority 2 — Medium Impact, Medium Effort

Gap	Impact	Effort	Details
Question/Poll support (inbound)	Medium	Medium	Poll posts from Mastodon render without options. Parse Question object's inclusiveOptions/exclusiveOptions, display vote options and results in timeline. Voting (outbound) is a separate feature.
Flag handler (inbound reports)	Medium	Medium	Other servers can't send us abuse reports. Add Flag inbox listener, store in a ap_reports collection, add moderation UI tab.
Content Warning / Sensitive flag (outbound)	Medium	Low	Inbound sensitive content is displayed with a warning. Add a "sensitive" / CW option to the compose form and syndicator so outbound posts can include content warnings.
Followers-only addressing	Medium	Medium	Add a "followers-only" visibility option. Requires to: followers only, no PUBLIC. Also needs consideration for who can see the post on our own site.

Priority 3 — Low Impact

Gap	Impact	Effort	Details
Custom Emoji	Low	Medium	Mastodon custom emoji renders as :shortcode: text. Parse Emoji tags, fetch images, inline-replace in content.
Reject(Follow) / manual approval	Low	Medium	Currently all follows are auto-accepted. Add a "manually approves followers" mode with pending/accept/reject UI.
Tombstone on delete	Low	Low	Instead of just deleting from collections, create a Tombstone object for the deleted resource. Mostly a federation correctness improvement.
Activity transformers	Low	Low	Fedify's actorDehydrator() improves Threads compatibility. Consider enabling for broader compatibility.
FEP-8fcf Followers Sync	Low	Low	Pass syncCollection: true to sendActivity() calls. Reduces duplicate deliveries for servers that support it.
FEP-fe34 Origin-Based Security	Low	Low	Set crossOrigin: "ignore" or "throw" on federation options. Prevents spoofed attribution attacks.

Not Recommended (Skip)

Gap	Reason
EmojiReact	Misskey/Pleroma-only, very niche
Arrive/Travel/Join/Leave	Almost never seen in real fediverse
Invite/Offer	Group-specific, very niche
Dislike	Not implemented by any major fediverse software
Relay support (FEP-ae0c)	Only useful at scale, not for personal sites
DID-based identity (FEP-9091)	Future spec, minimal adoption
Actor succession (FEP-c0e0)	Future spec, minimal adoption
ChatMessage (LitePub DMs)	Our standard DM addressing works with all servers

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12. Data Flow Reference

Outbound Activity Flow

Indiekit blog post (JF2)
  ↓
syndicator.syndicate()  [index.js]
  ↓
jf2ToAS2Activity()  [lib/jf2-to-as2.js — converts JF2 → Fedify vocab objects]
  ↓
ctx.sendActivity({ identifier: handle }, "followers", activity)  [Fedify]
  ↓
Redis queue  [or InProcessMessageQueue]
  ↓
HTTP POST to follower inboxes  [signed with RSA/Ed25519 by Fedify]

Inbound Activity Flow

Remote server HTTP POST to /{mount}/inbox  [HTTP Signature verified by Fedify]
  ↓
federation-bridge.js  [reconstructs body if Express consumed stream, uses req.originalUrl]
  ↓
Fedify matches activity type → calls registered listener
  ↓
inbox-listeners.js  [authenticated document loader for all remote fetches]
  ↓
MongoDB storage  [ap_followers, ap_timeline, ap_notifications, ap_messages, ap_activities]
  ↓
Admin UI renders data  [reader, notifications, messages, moderation]

Reader Timeline Pipeline

Raw items from ap_timeline
  ↓
applyTabFilter()  [notes/articles/boosts/media/replies — lib/item-processing.js]
  ↓
loadModerationData()  [load muted URLs, keywords, blocked URLs]
  ↓
postProcessItems()  [filter muted/blocked, strip quote refs, build interaction map]
  ↓
renderItemCards()  [server-side Nunjucks → HTML for AJAX responses]
  ↓
Alpine.js infinite scroll  [apInfiniteScroll component — assets/reader-infinite-scroll.js]

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13. MongoDB Collections Reference

Collection	Records	Indexes	TTL
ap_followers	Accounts following us	actorUrl (unique)	No
ap_following	Accounts we follow	actorUrl (unique)	No
ap_activities	Activity log	direction, type, actorUrl, objectUrl, receivedAt	Yes (activityRetentionDays, default 90)
ap_keys	Crypto key pairs	type (rsa/ed25519)	No
ap_kv	Fedify KV store	_id (key path)	Yes (Fedify-managed)
ap_profile	Actor profile (single doc)	—	No
ap_featured	Pinned posts	postUrl	No
ap_featured_tags	Featured hashtags	tag	No
ap_timeline	Reader timeline	uid (unique), published, author.url, type	No (manual cleanup via timelineRetention)
ap_notifications	Notifications	uid (unique), type, read, createdAt	Yes (notificationRetentionDays, default 30)
ap_messages	Direct messages	uid (unique), conversationId+published, read, direction	Yes (reuses notificationRetentionDays)
ap_muted	Muted actors/keywords	url or keyword	No
ap_blocked	Blocked actors	url	No
ap_interactions	Like/boost tracking	objectUrl, type	No
ap_followed_tags	Hashtags we follow	tag	No

---

14. Configuration Reference

{
  mountPath: "/activitypub",           // URL prefix for all routes
  actor: {
    handle: "rick",                    // Fediverse username (@rick@rmendes.net)
    name: "Ricardo Mendes",            // Display name (seeds profile on first run)
    summary: "",                       // Bio (seeds profile)
    icon: "",                          // Avatar URL (seeds profile)
  },
  checked: true,                       // Syndicator checked by default in Micropub UI
  alsoKnownAs: "",                     // Mastodon migration alias (for Move activities)
  activityRetentionDays: 90,           // TTL for ap_activities (0 = forever)
  storeRawActivities: false,           // Store full JSON of inbound activities
  redisUrl: "",                        // Redis for delivery queue (empty = in-process)
  parallelWorkers: 5,                  // Parallel delivery workers (with Redis)
  actorType: "Person",                 // Person | Service | Organization | Group | Application
  logLevel: "warning",                 // Fedify log level: debug | info | warning | error | fatal
  timelineRetention: 1000,             // Max timeline items (0 = unlimited)
  notificationRetentionDays: 30,       // Days to keep notifications (0 = forever)
  debugDashboard: false,               // Enable @fedify/debugger at {mount}/__debug__/
  debugPassword: "",                   // Password for debug dashboard
}

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This audit reflects the state of the plugin at version 2.9.2. It should be updated when new features are added or when Fedify releases new capabilities.