diff --git a/src/client/components/mention.vue b/src/client/components/mention.vue
index 0303e0e5b5..dd68aab146 100644
--- a/src/client/components/mention.vue
+++ b/src/client/components/mention.vue
@@ -18,6 +18,7 @@
 import Vue from 'vue';
 import { toUnicode } from 'punycode';
 import { host as localHost } from '../config';
+import { wellKnownServices } from '../../well-known-services';
 
 export default Vue.extend({
 	props: {
@@ -37,12 +38,11 @@ export default Vue.extend({
 	},
 	computed: {
 		url(): string {
-			switch (this.host) {
-				case 'twitter.com':
-				case 'github.com':
-					return `https://${this.host}/${this.username}`;
-				default:
-					return `/${this.canonical}`;
+			const wellKnown = wellKnownServices.find(x => x[0] === this.host);
+			if (wellKnown) {
+				return wellKnown[1](this.username);
+			} else {
+				return `/${this.canonical}`;
 			}
 		},
 		canonical(): string {
diff --git a/src/mfm/to-html.ts b/src/mfm/to-html.ts
index 1292292154..9376889829 100644
--- a/src/mfm/to-html.ts
+++ b/src/mfm/to-html.ts
@@ -3,6 +3,7 @@ import config from '../config';
 import { intersperse } from '../prelude/array';
 import { MfmForest, MfmTree } from './prelude';
 import { IMentionedRemoteUsers } from '../models/entities/note';
+import { wellKnownServices } from '../well-known-services';
 
 export function toHtml(tokens: MfmForest | null, mentionedRemoteUsers: IMentionedRemoteUsers = []) {
 	if (tokens == null) {
@@ -126,18 +127,13 @@ export function toHtml(tokens: MfmForest | null, mentionedRemoteUsers: IMentione
 		mention(token) {
 			const a = doc.createElement('a');
 			const { username, host, acct } = token.node.props;
-			switch (host) {
-				case 'github.com':
-					a.href = `https://github.com/${username}`;
-					break;
-				case 'twitter.com':
-					a.href = `https://twitter.com/${username}`;
-					break;
-				default:
-					const remoteUserInfo = mentionedRemoteUsers.find(remoteUser => remoteUser.username === username && remoteUser.host === host);
-					a.href = remoteUserInfo ? (remoteUserInfo.url ? remoteUserInfo.url : remoteUserInfo.uri) : `${config.url}/${acct}`;
-					a.className = 'u-url mention';
-					break;
+			const wellKnown = wellKnownServices.find(x => x[0] === host);
+			if (wellKnown) {
+				a.href = wellKnown[1](username);
+			} else {
+				const remoteUserInfo = mentionedRemoteUsers.find(remoteUser => remoteUser.username === username && remoteUser.host === host);
+				a.href = remoteUserInfo ? (remoteUserInfo.url ? remoteUserInfo.url : remoteUserInfo.uri) : `${config.url}/${acct}`;
+				a.className = 'u-url mention';
 			}
 			a.textContent = acct;
 			return a;
diff --git a/src/well-known-services.ts b/src/well-known-services.ts
new file mode 100644
index 0000000000..f47c540516
--- /dev/null
+++ b/src/well-known-services.ts
@@ -0,0 +1,4 @@
+export const wellKnownServices = [
+	['twitter.com', username => `https://twitter.com/${username}`],
+	['github.com', username => `https://github.com/${username}`],
+] as [string, (username: string) => string][];