diff --git a/package-lock.json b/package-lock.json
index 192133b..3be7e2d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -25,6 +25,7 @@
         "next": "^13.1.1",
         "next-axiom": "^0.16.0",
         "pdfjs-dist": "^3.1.81",
+        "prettier": "^2.8.3",
         "react": "18.2.0",
         "react-dom": "18.2.0",
         "react-resizable-panels": "~0.0.30",
@@ -4634,6 +4635,20 @@
         "node": ">= 0.8.0"
       }
     },
+    "node_modules/prettier": {
+      "version": "2.8.3",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.3.tgz",
+      "integrity": "sha512-tJ/oJ4amDihPoufT5sM0Z1SKEuKay8LfVAMlbbhnnkvt6BUserZylqo2PN+p9KeljLr0OHa2rXHU1T8reeoTrw==",
+      "bin": {
+        "prettier": "bin-prettier.js"
+      },
+      "engines": {
+        "node": ">=10.13.0"
+      },
+      "funding": {
+        "url": "https://github.com/prettier/prettier?sponsor=1"
+      }
+    },
     "node_modules/process-nextick-args": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/process-nextick-args/-/process-nextick-args-2.0.1.tgz",
@@ -9725,6 +9740,11 @@
       "integrity": "sha512-vkcDPrRZo1QZLbn5RLGPpg/WmIQ65qoWWhcGKf/b5eplkkarX0m9z8ppCat4mlOqUsWpyNuYgO3VRyrYHSzX5g==",
       "dev": true
     },
+    "prettier": {
+      "version": "2.8.3",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.3.tgz",
+      "integrity": "sha512-tJ/oJ4amDihPoufT5sM0Z1SKEuKay8LfVAMlbbhnnkvt6BUserZylqo2PN+p9KeljLr0OHa2rXHU1T8reeoTrw=="
+    },
     "process-nextick-args": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/process-nextick-args/-/process-nextick-args-2.0.1.tgz",
diff --git a/package.json b/package.json
index 25d401f..52439b1 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,7 @@
     "next": "^13.1.1",
     "next-axiom": "^0.16.0",
     "pdfjs-dist": "^3.1.81",
+    "prettier": "^2.8.3",
     "react": "18.2.0",
     "react-dom": "18.2.0",
     "react-resizable-panels": "~0.0.30",
diff --git a/pages/index.js b/pages/index.js
index 9ab9bca..a93f149 100644
--- a/pages/index.js
+++ b/pages/index.js
@@ -42,6 +42,7 @@ import {
 import { layoutAtom, selectedAtom } from "../state/debugger";
 
 import { code as defCode } from "../code/default-example";
+import { tryFormat } from "../worker/format-code";
 
 const compress = (string) =>
   LZString.compressToBase64(string)
@@ -331,6 +332,13 @@ const Repl = () => {
               )}
 
               <Buttons>
+                <button
+                  onClick={() =>
+                    tryFormat(code, (formattedCode) => setCode(formattedCode))
+                  }
+                >
+                  format
+                </button>
                 <button
                   onClick={() =>
                     navigator.clipboard.writeText(
diff --git a/worker/format-code.js b/worker/format-code.js
new file mode 100644
index 0000000..2eed816
--- /dev/null
+++ b/worker/format-code.js
@@ -0,0 +1,10 @@
+let formatter = null;
+
+export const tryFormat = (code, cb) => {
+  if (!formatter) {
+    formatter = new Worker(new URL("./prettier", import.meta.url));
+  }
+
+  formatter.onmessage = (event) => cb(event.data.code);
+  formatter.postMessage({ code });
+};
diff --git a/worker/prettier.js b/worker/prettier.js
new file mode 100644
index 0000000..7d557d8
--- /dev/null
+++ b/worker/prettier.js
@@ -0,0 +1,13 @@
+import prettier from "prettier";
+import parserEspree from "prettier/parser-espree";
+
+self.addEventListener("message", (e) => {
+  const { code } = e.data;
+
+  const formattedCode = prettier.format(code, {
+    parser: "espree",
+    plugins: [parserEspree],
+  });
+
+  self.postMessage({ code: formattedCode });
+});