Big Platforms and Their Quirks

Large platforms that joined the fediverse each made design choices your server will run into. This page lists the ones that affect interop, with sources. Where a platform's current behaviour couldn't be confirmed from a primary source, it says so.

Long-form posts show up as headline + link on Mastodon

Several of these platforms publish long-form posts as Article. Mastodon only fully supports Note and Question; for Article, Page, Image, Audio, Video and Event it builds the status from the name (as a heading), the summary, and a link to url — the content is not shown (status_parser.rb in Mastodon v4.7.3, CONVERTED_TYPES).

So if you publish blog posts as Article, Mastodon users see a title card that links back to your site. If you want the full text inline, publish a Note — at the cost of losing the title and long-form semantics. Other servers (Misskey forks, Akkoma, NodeBB) may render Article differently; test against the ones your users are on.

Threads (Meta)

Opt-in	Users aged 18+ with public profiles choose to federate (Meta engineering, March 2024)
What doesn't federate	Posts with restricted replies, replies to non-federated posts, polls, and reposts of non-federated posts (same source)
Quote posts	Sent using FEP-e232 object links plus _misskey_quote (same source) — not the consent-based FEP-044f that Mastodon 4.5+ uses
Links	Link attachments are appended to the post text when not already included (same source)

Current status: unverified. Meta has not published an engineering update on fediverse features since the 2024 post. A Meta engineer posted in June 2025 that Threads added a fediverse following feed and search, that replying to fediverse posts was a goal rather than a shipped feature, and that fediverse replies can be seen on Threads posts. Nothing newer from Meta could be confirmed; check before relying on reply behaviour.

Ghost

Since	Ghost 6.0, 4 August 2025 — "works on all Ghost 6.0 sites, whether on Ghost(Pro) or self-hosted"
Implementation	A separate, multi-tenant ActivityPub service built with Fedify; Ghost proxies /.ghost/activitypub/*, /.well-known/webfinger and /.well-known/nodeinfo to it
Long-form posts	Sent as Article with name, content, summary, image and url, plus a preview Note holding the excerpt (source) — so Mastodon shows a title card and link (see above)
Short notes	Sent as Note with image attachments and mentions (same source)

If your server can render preview, it is a better excerpt than summary for Ghost articles.

WordPress (ActivityPub plugin)

The ActivityPub plugin (Automattic; 9.3.1 released 2026-09-02) documents its behaviour in FEDERATION.md:

• Object types: Note by default; Article for standard posts without a specific post format — which Mastodon shows as a title card.
• Signatures: signs all outgoing POSTs and supports signed GETs. Since 8.1 it retries failed deliveries with the other signature format ("double-knock", PR #3098); 9.0 binds RFC 9421 keyIds to the actor's host (PR #3357).
• Client-to-server: 8.1.0 (2026-04-21) added a C2S API with OAuth; 9.0.0 improved conformance with the SWICG Basic Profile (listed as partial). This is one of the few production C2S implementations — useful to test clients against.
• FEPs: among others FEP-044f (quote posts), FEP-7628 (Move), FEP-7888 (context), FEP-8fcf (followers sync), FEP-b2b8 (long-form text), FEP-c180 (problem details), FEP-7aa9 consent endpoint (9.0).

NodeBB

NodeBB (v4.16.3, 2026-10-14) federates forums (NodeBB ActivityPub docs):

• Categories are Group actors following FEP-1b12: when anyone posts in a category, the category Announces the post to its followers. Categories can also follow other Group actors.
• audience is set to the category; the topic is expressed in context.
• Threads: NodeBB first resolves the FEP-7888 context as a collection and imports every object in it; if there is no resolvable context, it walks the inReplyTo chain to the root. Publish a resolvable context collection if you want your threads to arrive whole.
• Remote content that isn't in a followed category lands in an "Uncategorized" pseudo-category.

Discourse (ActivityPub plugin)

The discourse-activity-pub plugin publishes categories and tags as actors. From its settings and messages:

• Two publication modes per actor: first post only or full topic ("Full topic publication requires public publication").
• Delivery is delayed by 5 minutes by default (activity_pub_delivery_delay_minutes); deletes are delivered immediately. Don't expect a new topic to arrive the moment it is posted.
• Signed requests are required by default (activity_pub_require_signed_requests) — sign your GETs.
• Editing a note after publication is not supported.

Bridgy Fed

Bridgy Fed bridges the fediverse, Bluesky and websites. Per its docs:

Who	Bridged handle
Bluesky user, seen from the fediverse	@handle@bsky.brid.gy, e.g. @snarfed.bsky.social@bsky.brid.gy
Fediverse user, seen from Bluesky	user.instance.ap.brid.gy, e.g. @snarfed@indieweb.social → snarfed.indieweb.social.ap.brid.gy (underscores and tildes become dashes)
Website, seen from Bluesky	yourdomain.com.web.brid.gy
Website, seen from the fediverse	@yourdomain.com@yourdomain.com by default

• Opt-in on both sides: fediverse users follow @bsky.brid.gy@bsky.brid.gy (block it to opt out); Bluesky users follow @ap.brid.gy.
• Only fully public posts are bridged. Unlisted, followers-only posts and DMs never are.
• Nostr is not supported — the docs say only that Farcaster and Nostr are being considered.

If your server shows remote handles, bsky.brid.gy and web.brid.gy actors are bridges: link them to the original account where you can.

Flipboard and Surf

Surf is Flipboard's client for the open social web, reaching people "on the ATproto network as well as those on ActivityPub"; as of Flipboard's March 2025 announcement it was in private beta, with Bluesky login and Mastodon account linking. Later launch status is unverified.

Tumblr

Unverified. Tumblr does not federate. Automattic's plan to move Tumblr onto WordPress — which would have brought the ActivityPub plugin with it — was reported in June 2025 to be on hold. No primary source from Automattic or Tumblr staff was found.

See also

• Bridges
• Mastodon
• Server software