diff --git a/.github/workflows/typecheck.yml b/.github/workflows/typecheck.yml
new file mode 100644
index 0000000..9142f17
--- /dev/null
+++ b/.github/workflows/typecheck.yml
@@ -0,0 +1,21 @@
+name: TypeCheck
+on: [pull_request, push]
+
+jobs:
+  typecheck:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Run TypeScript check
+        run: npx tsc
diff --git a/.gitignore b/.gitignore
index c476faf..8a67d8e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -38,3 +38,7 @@ hs_err_*.log
 replay_*.log
 *.hprof
 *.jfr
+
+# node
+
+node_modules/
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..08c60fc
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,26 @@
+{
+  "name": "minecraft-web-chat",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "devDependencies": {
+        "typescript": "^5.7.2"
+      }
+    },
+    "node_modules/typescript": {
+      "version": "5.7.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.7.2.tgz",
+      "integrity": "sha512-i5t66RHxDvVN40HfDd1PsEThGNnlMCMT3jMUuoh9/0TaqWevNontacunWyN02LA9/fIbEWlcHZcgTKb9QoaLfg==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=14.17"
+      }
+    }
+  }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..279d638
--- /dev/null
+++ b/package.json
@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "typescript": "^5.7.2"
+  }
+}
diff --git a/src/client/resources/web/js/message_parsing.mjs b/src/client/resources/web/js/message_parsing.mjs
index 9e63f7d..8ccdd69 100644
--- a/src/client/resources/web/js/message_parsing.mjs
+++ b/src/client/resources/web/js/message_parsing.mjs
@@ -89,13 +89,13 @@ function escapeHtml(unsafe) {
         return '';
     }
     return unsafe
-        .replace(/&/g, '&')
-        .replace(/</g, '&lt;')
-        .replace(/>/g, '&gt;')
-        .replace(/"/g, '&quot;')
-        .replace(/'/g, '&#039;')
-        .replace(/`/g, '&#x60;')
-        .replace(/\\/g, '&#x5c;');
+        .replaceAll('&', '&amp;')
+        .replaceAll('<', '&lt;')
+        .replaceAll('>', '&gt;')
+        .replaceAll('"', '&quot;')
+        .replaceAll("'", '&#039;')
+        .replaceAll('`', '&#x60;')
+        .replaceAll('\\', '&#x5c;');
 }
 
 // Imitates Minecraft's obfuscated text. 
@@ -132,6 +132,8 @@ export function initializeObfuscation() {
 
             for (let i = 0; i < elementsToProcess; i++) {
                 const element = elements[i];
+                if (!element) continue;
+
                 const length = element.textContent ? element.textContent.length : 0;
                 let result = '';
 
diff --git a/src/client/resources/web/js/translations.mjs b/src/client/resources/web/js/translations.mjs
index a15afae..0928197 100644
--- a/src/client/resources/web/js/translations.mjs
+++ b/src/client/resources/web/js/translations.mjs
@@ -2,6 +2,7 @@
 'use strict';
 
 // https://github.com/PrismarineJS/minecraft-data 1.21.1
+/** @type {Record<string, string>} */
 export const translations = {
     "accessibility.onboarding.accessibility.button": "Accessibility Settings...",
     "accessibility.onboarding.screen.narrator": "Press enter to enable the narrator",
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..754e59e
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,44 @@
+{
+    "compilerOptions": {
+      "lib": ["dom", "ES2021"],
+
+      // JavaScript Support
+      "allowJs": true,
+      "checkJs": true,
+      "noEmit": true,
+  
+      // Module Settings
+      "module": "ES2020",
+      "moduleResolution": "node",
+      "target": "ES2021",
+  
+      // Strictness
+      "strict": true,
+      "noImplicitAny": true,
+      "strictNullChecks": true,
+      "strictFunctionTypes": true,
+      "strictBindCallApply": true,
+      "strictPropertyInitialization": true,
+      "noImplicitThis": true,
+      "useUnknownInCatchVariables": true,
+      "alwaysStrict": true,
+      "noImplicitReturns": true,
+      "noFallthroughCasesInSwitch": true,
+      "noUncheckedIndexedAccess": true,
+      "noImplicitOverride": true,
+      "noPropertyAccessFromIndexSignature": true,
+  
+      // Additional Safety
+      "forceConsistentCasingInFileNames": true,
+      "skipLibCheck": true,
+      "verbatimModuleSyntax": true,
+      "isolatedModules": true
+    },
+    "include": [
+      "src/client/resources/web/js/**/*.js",
+      "src/client/resources/web/js/**/*.mjs"
+    ],
+    "exclude": [
+      "node_modules"
+    ]
+}