diff --git a/src/activitypub/mocks.js b/src/activitypub/mocks.js
index 7211568e4c..e0db3e030d 100644
--- a/src/activitypub/mocks.js
+++ b/src/activitypub/mocks.js
@@ -2,10 +2,13 @@
 
 const nconf = require('nconf');
 const mime = require('mime');
+const path = require('path');
 
 const user = require('../user');
+const categories = require('../categories');
 const posts = require('../posts');
 const topics = require('../topics');
+const utils = require('../utils');
 
 const activitypub = module.parent.exports;
 const Mocks = module.exports;
@@ -111,7 +114,9 @@ Mocks.post = async (objects) => {
 	return single ? posts.pop() : posts;
 };
 
-Mocks.actor = async (uid) => {
+Mocks.actors = {};
+
+Mocks.actors.user = async (uid) => {
 	let { username, userslug, displayname: name, aboutme, picture, 'cover:url': cover } = await user.getUserData(uid);
 	const publicKey = await activitypub.getPublicKey(uid);
 
@@ -157,6 +162,36 @@ Mocks.actor = async (uid) => {
 	};
 };
 
+Mocks.actors.category = async (cid) => {
+	let { name, slug, description: summary, backgroundImage } = await categories.getCategoryData(cid);
+
+	if (backgroundImage) {
+		const filename = utils.decodeHTMLEntities(backgroundImage).split('/').pop();
+		const imagePath = path.join(nconf.get('upload_path'), 'category', filename);
+		backgroundImage = {
+			type: 'Image',
+			mediaType: mime.getType(imagePath),
+			url: `${nconf.get('url')}${utils.decodeHTMLEntities(backgroundImage)}`,
+		};
+	}
+
+	return {
+		'@context': 'https://www.w3.org/ns/activitystreams',
+		id: `${nconf.get('url')}/category/${cid}`,
+		url: `${nconf.get('url')}/category/${slug}`,
+		// followers: ,
+		//  following: ,
+		inbox: `${nconf.get('url')}/category/${cid}/inbox`,
+		outbox: `${nconf.get('url')}/category/${cid}/outbox`,
+
+		type: 'Group',
+		name,
+		preferredUsername: name,
+		summary,
+		icon: backgroundImage,
+	};
+};
+
 Mocks.note = async (post) => {
 	const id = `${nconf.get('url')}/post/${post.pid}`;
 	const published = new Date(parseInt(post.timestamp, 10)).toISOString();
diff --git a/src/api/activitypub.js b/src/api/activitypub.js
index 73f671da87..2152a75444 100644
--- a/src/api/activitypub.js
+++ b/src/api/activitypub.js
@@ -88,7 +88,7 @@ activitypubApi.update = {};
 
 activitypubApi.update.profile = async (caller, { uid }) => {
 	const [object, followers] = await Promise.all([
-		activitypub.mocks.actor(uid),
+		activitypub.mocks.actors.user(uid),
 		db.getSortedSetMembers(`followersRemote:${caller.uid}`),
 	]);
 
diff --git a/src/controllers/activitypub/actors.js b/src/controllers/activitypub/actors.js
index 4cd9fe240a..adf7758157 100644
--- a/src/controllers/activitypub/actors.js
+++ b/src/controllers/activitypub/actors.js
@@ -4,6 +4,7 @@ const nconf = require('nconf');
 
 const meta = require('../../meta');
 const posts = require('../../posts');
+const categories = require('../../categories');
 const activitypub = require('../../activitypub');
 
 const Actors = module.exports;
@@ -33,7 +34,7 @@ Actors.application = async function (req, res) {
 
 Actors.user = async function (req, res) {
 	// todo: view:users priv gate
-	const payload = await activitypub.mocks.actor(req.params.uid);
+	const payload = await activitypub.mocks.actors.user(req.params.uid);
 
 	res.status(200).json(payload);
 };
@@ -56,3 +57,13 @@ Actors.note = async function (req, res, next) {
 	const payload = await activitypub.mocks.note(post);
 	res.status(200).json(payload);
 };
+
+Actors.category = async function (req, res, next) {
+	const exists = await categories.exists(req.params.cid);
+	if (!exists) {
+		return next('route');
+	}
+
+	const payload = await activitypub.mocks.actors.category(req.params.cid);
+	res.status(200).json(payload);
+};
diff --git a/src/controllers/activitypub/index.js b/src/controllers/activitypub/index.js
index 8ae0ef98f6..d742af7d9a 100644
--- a/src/controllers/activitypub/index.js
+++ b/src/controllers/activitypub/index.js
@@ -90,6 +90,16 @@ Controller.getOutbox = async (req, res) => {
 	});
 };
 
+Controller.getCategoryOutbox = async (req, res) => {
+	// stub
+	res.status(200).json({
+		'@context': 'https://www.w3.org/ns/activitystreams',
+		type: 'OrderedCollection',
+		totalItems: 0,
+		orderedItems: [],
+	});
+};
+
 Controller.postOutbox = async (req, res) => {
 	// This is a client-to-server feature so it is deliberately not implemented at this time.
 	res.sendStatus(405);
diff --git a/src/controllers/well-known.js b/src/controllers/well-known.js
index 2f4698613f..7cad3a9553 100644
--- a/src/controllers/well-known.js
+++ b/src/controllers/well-known.js
@@ -3,6 +3,7 @@
 const nconf = require('nconf');
 
 const user = require('../user');
+const categories = require('../categories');
 const privileges = require('../privileges');
 
 const Controller = module.exports;
@@ -15,53 +16,86 @@ Controller.webfinger = async (req, res) => {
 		return res.sendStatus(400);
 	}
 
-	const canView = await privileges.global.can('view:users', req.uid);
-	if (!canView) {
-		return res.sendStatus(403);
-	}
-
 	// Get the slug
 	const slug = resource.slice(5, resource.length - (host.length + 1));
-
-	let uid = await user.getUidByUserslug(slug);
-	if (slug === hostname) {
-		uid = 0;
-	} else if (!uid) {
-		return res.sendStatus(404);
-	}
-
-	const response = {
+	const uid = await user.getUidByUserslug(slug);
+	let response = {
 		subject: `acct:${slug}@${host}`,
 	};
 
-	if (uid) {
-		response.aliases = [
-			`${nconf.get('url')}/uid/${uid}`,
-			`${nconf.get('url')}/user/${slug}`,
-		];
+	try {
+		if (slug.startsWith('cid.')) {
+			response = await category(req.uid, slug.slice(4), response);
+		} else if (slug === hostname) {
+			response = application(response);
+		} else if (uid) {
+			response = await profile(req.uid, uid, response);
+		} else {
+			return res.sendStatus(404);
+		}
 
-		response.links = [
-			{
-				rel: 'self',
-				type: 'application/activity+json',
-				href: `${nconf.get('url')}/uid/${uid}`, // actor
-			},
-			{
-				rel: 'http://webfinger.net/rel/profile-page',
-				type: 'text/html',
-				href: `${nconf.get('url')}/user/${slug}`,
-			},
-		];
-	} else {
-		response.aliases = [nconf.get('url')];
-		response.links = [
-			{
-				rel: 'self',
-				type: 'application/activity+json',
-				href: `${nconf.get('url')}/actor`, // actor
-			},
-		];
+		res.status(200).json(response);
+	} catch (e) {
+		res.sendStatus(400);
 	}
-
-	res.status(200).json(response);
 };
+
+function application(response) {
+	response.aliases = [nconf.get('url')];
+	response.links = [
+		{
+			rel: 'self',
+			type: 'application/activity+json',
+			href: `${nconf.get('url')}/actor`, // actor
+		},
+	];
+
+	return response;
+}
+
+async function profile(callerUid, uid, response) {
+	const canView = await privileges.global.can('view:users', callerUid);
+	if (!canView) {
+		throw new Error('[[error:no-privileges]]');
+	}
+	const slug = await user.getUserField(uid, 'userslug');
+
+	response.aliases = [
+		`${nconf.get('url')}/uid/${uid}`,
+		`${nconf.get('url')}/user/${slug}`,
+	];
+
+	response.links = [
+		{
+			rel: 'self',
+			type: 'application/activity+json',
+			href: `${nconf.get('url')}/uid/${uid}`, // actor
+		},
+		{
+			rel: 'http://webfinger.net/rel/profile-page',
+			type: 'text/html',
+			href: `${nconf.get('url')}/user/${slug}`,
+		},
+	];
+
+	return response;
+}
+
+async function category(callerUid, cid, response) {
+	const canFind = await privileges.categories.can('find', cid, callerUid);
+	if (!canFind) {
+		throw new Error('[[error:no-privileges]]');
+	}
+	const slug = await categories.getCategoryField(cid, 'slug');
+
+	response.aliases = [`${nconf.get('url')}/category/${slug}`];
+	response.links = [
+		{
+			rel: 'self',
+			type: 'application/activity+json',
+			href: `${nconf.get('url')}/category/${cid}`, // actor
+		},
+	];
+
+	return response;
+}
diff --git a/src/routes/activitypub.js b/src/routes/activitypub.js
index ffc3a52bcd..5d136398f5 100644
--- a/src/routes/activitypub.js
+++ b/src/routes/activitypub.js
@@ -15,17 +15,21 @@ module.exports = function (app, middleware, controllers) {
 	const middlewares = [middleware.activitypub.enabled, middleware.activitypub.assertS2S];
 
 	app.get('/actor', middlewares, controllers.activitypub.actors.application);
+
 	app.get('/uid/:uid', middlewares, controllers.activitypub.actors.user);
 	app.get('/user/:userslug', [...middlewares, middleware.exposeUid], controllers.activitypub.actors.userBySlug);
-
 	app.get('/uid/:uid/inbox', middlewares, controllers.activitypub.getInbox);
 	app.post('/uid/:uid/inbox', [...middlewares, middleware.activitypub.validate], controllers.activitypub.postInbox);
-
 	app.get('/uid/:uid/outbox', middlewares, controllers.activitypub.getOutbox);
 	app.post('/uid/:uid/outbox', middlewares, controllers.activitypub.postOutbox);
-
 	app.get('/uid/:uid/following', middlewares, controllers.activitypub.getFollowing);
 	app.get('/uid/:uid/followers', middlewares, controllers.activitypub.getFollowers);
 
 	app.get('/post/:pid', middlewares, controllers.activitypub.actors.note);
+
+	app.get('/category/:cid', middlewares, controllers.activitypub.actors.category);
+	app.get('/category/:cid/inbox', middlewares, controllers.activitypub.getInbox);
+	app.post('/category/:cid/inbox', [...middlewares, middleware.activitypub.validate], controllers.activitypub.postInbox);
+	app.get('/category/:cid/outbox', middlewares, controllers.activitypub.getCategoryOutbox);
+	app.post('/category/:cid/outbox', middlewares, controllers.activitypub.postOutbox);
 };