diff --git a/src/activitypub/helpers.js b/src/activitypub/helpers.js
index e77a5280d8..fb0504e386 100644
--- a/src/activitypub/helpers.js
+++ b/src/activitypub/helpers.js
@@ -9,6 +9,7 @@ const request = require('../request');
 const db = require('../database');
 const ttl = require('../cache/ttl');
 const user = require('../user');
+const activitypub = require('.');
 
 const webfingerCache = ttl({ ttl: 1000 * 60 * 60 * 24 }); // 24 hours
 
@@ -57,7 +58,7 @@ Helpers.query = async (id) => {
 	}
 
 	// Parse links to find actor endpoint
-	let actorUri = body.links.filter(link => link.type === 'application/activity+json' && link.rel === 'self');
+	let actorUri = body.links.filter(link => activitypub._constants.acceptableTypes.includes(link.type) && link.rel === 'self');
 	if (actorUri.length) {
 		actorUri = actorUri.pop();
 		({ href: actorUri } = actorUri);
diff --git a/src/activitypub/index.js b/src/activitypub/index.js
index 54ab2c64ba..8cf1066886 100644
--- a/src/activitypub/index.js
+++ b/src/activitypub/index.js
@@ -17,6 +17,10 @@ const ActivityPub = module.exports;
 ActivityPub._constants = Object.freeze({
 	uid: -2,
 	publicAddress: 'https://www.w3.org/ns/activitystreams#Public',
+	acceptableTypes: [
+		'application/activity+json',
+		'application/ld+json; profile="https://www.w3.org/ns/activitystreams"',
+	],
 });
 ActivityPub._cache = requestCache;
 
diff --git a/src/middleware/activitypub.js b/src/middleware/activitypub.js
index 81f104dea1..bcb6dd9b1d 100644
--- a/src/middleware/activitypub.js
+++ b/src/middleware/activitypub.js
@@ -18,14 +18,10 @@ middleware.assertS2S = async function (req, res, next) {
 		return next('route');
 	}
 
-	const acceptable = [
-		'application/activity+json',
-		'application/ld+json; profile="https://www.w3.org/ns/activitystreams"',
-	];
 	const pass = (accept && accept.split(',').some((value) => {
 		const parts = value.split(';').map(v => v.trim());
-		return acceptable.includes(value || parts[0]);
-	})) || (contentType && acceptable.includes(contentType));
+		return activitypub._constants.acceptableTypes.includes(value || parts[0]);
+	})) || (contentType && activitypub._constants.acceptableTypes.includes(contentType));
 
 	if (!pass) {
 		return next('route');