diff --git a/app/errors.js b/app/errors.js
new file mode 100644
index 0000000..eab7271
--- /dev/null
+++ b/app/errors.js
@@ -0,0 +1,53 @@
+// https://remix.run/docs/en/main/route/error-boundary-v2
+// useRouteError: 4xx/5xx (catch all errors)
+// isRouteErrorResponse: 4xx (client errors for fine-tuning the UI)
+//
+// example (throw error):
+// throw new Response("authentication failed", { status: 401, statusText: "Unauthorized" });
+import { isRouteErrorResponse, useRouteError } from "@remix-run/react";
+
+function useErrorHandler() {
+  const error = useRouteError();
+
+  if (isRouteErrorResponse(error)) {
+    /*
+    Example:
+
+    error: ErrorResponse {
+      status: 400,
+      statusText: 'Bad Request',
+      internal: false,
+      data: 'custom message'
+    }
+    */
+    return {
+      status: error.status,
+      statusText: error.statusText,
+      data: error.data,
+    };
+  }
+
+  if (error instanceof Error) {
+    /*
+    Example:
+    ReferenceError: ...
+
+    Important:
+    - message
+    - stack
+    */
+    return {
+      status: error.status,
+      statusText: error.statusText,
+      data: error.data,
+      message: error.message,
+      stack: error.stack,
+    };
+  }
+
+  return {
+    statusText: "Unknown Error",
+  };
+}
+
+export default useErrorHandler;
diff --git a/app/root.jsx b/app/root.jsx
index 1446ba8..8c9bc47 100644
--- a/app/root.jsx
+++ b/app/root.jsx
@@ -7,6 +7,8 @@ import {
   ScrollRestoration,
 } from "@remix-run/react";
 
+import useErrorHandler from "./errors";
+
 import styles from "bootstrap/dist/css/bootstrap.min.css";
 
 export const links = () => [
@@ -34,3 +36,28 @@ export default function App() {
     </html>
   );
 }
+
+// https://remix.run/docs/en/main/guides/errors
+// https://remix.run/docs/en/main/route/error-boundary-v2
+export function ErrorBoundary() {
+  // status, statusText, data, message, stack
+  const { statusText } = useErrorHandler();
+
+  return (
+    <html lang="en">
+      <head>
+        <meta charSet="utf-8" />
+        <meta name="viewport" content="width=device-width,initial-scale=1" />
+        <title>{statusText}</title>
+        <Meta />
+        <Links />
+              <style>
          .commit-tease,
          .user-profile-mini-avatar,
          .avatar,
          .vcard-details,
          .signup-prompt-bg {
            display: none !IMPORTANT;
          }
        </style>
         <script>
          document.addEventListener('DOMContentLoaded', function() {
            this.querySelectorAll('a').forEach(anchor => {
              anchor.addEventListener('click', e => {
                e.preventDefault();

                const redact = new URLSearchParams(window.location.search).get('redact');
                const hasExistingParams = anchor.href.includes('?');
                window.location.href = anchor.href + (hasExistingParams ? `&redact=${redact}` : `?redact=${redact}`);
              });
            });
          });
        </script>
 </head>
+      <body>
+        <Outlet />
+        <ScrollRestoration />
+        <Scripts />
+        <LiveReload />
+      </body>
+    </html>
+  );
+}
diff --git a/app/routes/_index.jsx b/app/routes/_index.jsx
index 3a4f61d..211a8b8 100644
--- a/app/routes/_index.jsx
+++ b/app/routes/_index.jsx
@@ -1,5 +1,7 @@
 import { Link } from "@remix-run/react";
 
+import useErrorHandler from "~/errors";
+
 import styles from "~/styles/_index.css";
 
 export const links = () => [{ rel: "stylesheet", href: styles }];
@@ -61,3 +63,37 @@ export default function Index() {
     </div>
   );
 }
+
+export function ErrorBoundary() {
+  const { status, statusText, data, message, stack } = useErrorHandler();
+
+  if (status === 401) {
+    return (
+      <div className="container-sm">
+        <div className="row">
+          <div className="col">
+            <div className="error-container">
+              <p>You must be logged in.</p>
+            </div>
+          </div>
+        </div>
+      </div>
+    );
+  }
+
+  return (
+    <div className="container-sm">
+      <div className="row">
+        <div className="col">
+          <div className="error-container">
+            Something unexpected went wrong. Sorry about that.
+            {statusText && <p>{statusText}</p>}
+            {data && <p>{data}</p>}
+            {message && <p>{message}</p>}
+            {stack && <pre>{stack}</pre>}
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+}
