diff --git a/package.json b/package.json
index 0a22143..c9f4ab3 100644
--- a/package.json
+++ b/package.json
@@ -18,6 +18,7 @@
     "babel-loader": "^7.1.2",
     "babel-preset-env": "^1.6.1",
     "markdown-it": "^8.4.0",
+    "@types/markdown-it": "^10.0.0",
     "standard": "^10.0.3",
     "webpack": "^3.10.0",
     "webpack-node-externals": "^1.6.0",
diff --git a/types/index.d.ts b/types/index.d.ts
new file mode 100644
index 0000000..92c345f
--- /dev/null
+++ b/types/index.d.ts
@@ -0,0 +1,21 @@
+/*
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+declare module 'markdown-it-regex' {
+  import MarkdownIt from 'markdown-it/lib'
+
+  namespace markdownItRegex {
+    export interface RegexOptions {
+      name: string,
+      regex: RegExp,
+      replace: (match: string) => string
+    }
+  }
+
+  const markdownItRegex: MarkdownIt.PluginWithOptions<markdownItRegex.RegexOptions>
+
+  export = markdownItRegex
+}
diff --git a/yarn.lock b/yarn.lock
index 6803957..e4ee40b 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2,6 +2,31 @@
 # yarn lockfile v1
 
 
+"@types/highlight.js@^9.7.0":
+  version "9.12.4"
+  resolved "https://registry.yarnpkg.com/@types/highlight.js/-/highlight.js-9.12.4.tgz#8c3496bd1b50cc04aeefd691140aa571d4dbfa34"
+  integrity sha512-t2szdkwmg2JJyuCM20e8kR2X59WCE5Zkl4bzm1u1Oukjm79zpbiAv+QjnwLnuuV0WHEcX2NgUItu0pAMKuOPww==
+
+"@types/linkify-it@*":
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/@types/linkify-it/-/linkify-it-3.0.0.tgz#c0ca4c253664492dbf47a646f31cfd483a6bbc95"
+  integrity sha512-x9OaQQTb1N2hPZ/LWJsqushexDvz7NgzuZxiRmZio44WPuolTZNHDBCrOxCzRVOMwamJRO2dWax5NbygOf1OTQ==
+
+"@types/markdown-it@^10.0.0":
+  version "10.0.3"
+  resolved "https://registry.yarnpkg.com/@types/markdown-it/-/markdown-it-10.0.3.tgz#a9800d14b112c17f1de76ec33eff864a4815eec7"
+  integrity sha512-daHJk22isOUvNssVGF2zDnnSyxHhFYhtjeX4oQaKD6QzL3ZR1QSgiD1g+Q6/WSWYVogNXYDXODtbgW/WiFCtyw==
+  dependencies:
+    "@types/highlight.js" "^9.7.0"
+    "@types/linkify-it" "*"
+    "@types/mdurl" "*"
+    highlight.js "^9.7.0"
+
+"@types/mdurl@*":
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/@types/mdurl/-/mdurl-1.0.2.tgz#e2ce9d83a613bacf284c7be7d491945e39e1f8e9"
+  integrity sha512-eC4U9MlIcu2q0KQmXszyn5Akca/0jrQmwDRgpAMJai7qBWq4amIQhZyNau4VYGtCeALvW1/NtjzJJ567aZxfKA==
+
 abbrev@1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/abbrev/-/abbrev-1.1.1.tgz#f8f2c887ad10bf67f634f005b6987fed3179aac8"
@@ -1779,6 +1804,11 @@ hawk@3.1.3, hawk@~3.1.3:
     hoek "2.x.x"
     sntp "1.x.x"
 
+highlight.js@^9.7.0:
+  version "9.18.5"
+  resolved "https://registry.yarnpkg.com/highlight.js/-/highlight.js-9.18.5.tgz#d18a359867f378c138d6819edfc2a8acd5f29825"
+  integrity sha512-a5bFyofd/BHCX52/8i8uJkjr9DYwXIPnM/plwI6W7ezItLGqzt7X2G2nXuYSfsIJdkwwj/g9DG1LkcGJI/dDoA==
+
 hmac-drbg@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/hmac-drbg/-/hmac-drbg-1.0.1.tgz#d2745701025a6c775a6c545793ed502fc0c649a1"