diff --git a/package.json b/package.json
index d7a8b859d..8fc379822 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,7 @@
   },
   "devDependencies": {
     "eslint": "2.7.0",
+    "highlightjs": "^8.7.0",
     "json-loader": "0.5.4",
     "scratch-blocks": "git+https://git@github.com/LLK/scratch-blocks.git",
     "tap": "5.7.1",
diff --git a/playground/index.html b/playground/index.html
index 657b6ba3a..cbb7c2ac5 100644
--- a/playground/index.html
+++ b/playground/index.html
@@ -5,12 +5,13 @@
     <meta charset="utf-8">
     <title>Scratch VM Playground</title>
     <link rel="stylesheet" href="playground.css">
+    <link rel="stylesheet" href="../node_modules/highlightjs/styles/zenburn.css">
 </head>
 <body>
     <div id="vm-devtools">
         <div id="tab-blockexplorer">
             <h2>VM Block Representation</h2>
-            <textarea id="blockexplorer" spellcheck="false"></textarea>
+            <pre id="blockexplorer"></pre>
         </div>
     </div>
     <div id="blocks"></div>
@@ -75,6 +76,8 @@
       </category>
     </xml>
 
+    <!-- Syntax highlighter -->
+    <script src="../node_modules/highlightjs/highlight.pack.min.js"></script>
     <!-- Scratch Blocks -->
     <!-- For easier development between the two, use `npm link` -->
     <script src="../node_modules/scratch-blocks/blockly_compressed_vertical.js"></script>
diff --git a/playground/playground.css b/playground/playground.css
index 294746ce6..f1a54242e 100644
--- a/playground/playground.css
+++ b/playground/playground.css
@@ -20,7 +20,8 @@ body {
 #blockexplorer {
     position: absolute;
     width: 100%;
-    height: 90%;
+    height: 80%;
+    overflow: scroll;
     border: 1px solid #fff;
     background: rgb(36,36,36);
     color: rgb(217,217,217);
diff --git a/playground/playground.js b/playground/playground.js
index d4caf06c9..1b8b99523 100644
--- a/playground/playground.js
+++ b/playground/playground.js
@@ -18,6 +18,7 @@ window.onload = function() {
     workspace.addChangeListener(function() {
         // On a change, update the block explorer.
         explorer.innerHTML = JSON.stringify(vm.runtime.blocks, null, 2);
+        window.hljs.highlightBlock(explorer);
     });
 
     // Run threads
