An example of building a federated server application using Fedify with SolidStart. It serves a single demo actor over ActivityPub, so it can be looked up and followed from other federated platforms such as Mastodon or Misskey.

Federation is wired up in src/lib/federation.ts and mounted through fedifyMiddleware() in src/middleware/index.ts. Keys and follower relationships are kept in memory, so they are discarded whenever the server restarts.

pnpm install
pnpm dev

The server listens on http://localhost:3000/, which redirects to the demo actor's profile page.

The example exposes one actor, demo, at http://localhost:3000/users/demo:

curl -H "Accept: application/activity+json" http://localhost:3000/users/demo

WebFinger and NodeInfo are served too:

curl "http://localhost:3000/.well-known/webfinger?resource=acct:demo@localhost:3000"
curl http://localhost:3000/nodeinfo/2.1

1. Tunnel your local server to the internet using fedify tunnel:

   fedify tunnel 3000

2. Open the tunneled URL in your browser and check that the server is running properly.

3. Search for @demo@<your tunneled host> from another federated server and follow it. The example answers a Follow with an Accept and records the follower, so the follower count on the profile page goes up.

   [!NOTE] ActivityPub Academy is a great resource to learn how to interact with other federated servers using the ActivityPub protocol.