diff --git a/apps/journal/app/root.tsx b/apps/journal/app/root.tsx
index ca53230..f68979f 100644
--- a/apps/journal/app/root.tsx
+++ b/apps/journal/app/root.tsx
@@ -1,5 +1,6 @@
-import { Links, Meta, Outlet, Scripts, ScrollRestoration } from "react-router";
+import { Links, Meta, Outlet, Scripts, ScrollRestoration, isRouteErrorResponse } from "react-router";
 import type { LinksFunction } from "react-router";
+import type { Route } from "./+types/root";
 import stylesheet from "@trails-cool/ui/styles.css?url";
 
 export const links: LinksFunction = () => [{ rel: "stylesheet", href: stylesheet }];
@@ -25,3 +26,33 @@ export function Layout({ children }: { children: React.ReactNode }) {
 export default function App() {
   return <Outlet />;
 }
+
+export function ErrorBoundary({ error }: Route.ErrorBoundaryProps) {
+  if (isRouteErrorResponse(error)) {
+    return (
+      <div className="mx-auto max-w-md px-4 py-16 text-center">
+        <h1 className="text-4xl font-bold text-gray-900">{error.status}</h1>
+        <p className="mt-2 text-gray-600">
+          {error.status === 404 && "Page not found"}
+          {error.status === 503 && "Service temporarily unavailable. Please try again later."}
+          {error.status !== 404 && error.status !== 503 && (error.statusText || "Something went wrong")}
+        </p>
+        <a href="/" className="mt-6 inline-block text-blue-600 hover:underline">
+          Go home
+        </a>
+      </div>
+    );
+  }
+
+  return (
+    <div className="mx-auto max-w-md px-4 py-16 text-center">
+      <h1 className="text-4xl font-bold text-gray-900">Error</h1>
+      <p className="mt-2 text-gray-600">
+        {error instanceof Error ? error.message : "An unexpected error occurred"}
+      </p>
+      <a href="/" className="mt-6 inline-block text-blue-600 hover:underline">
+        Go home
+      </a>
+    </div>
+  );
+}
diff --git a/apps/planner/app/root.tsx b/apps/planner/app/root.tsx
index 17b1eb6..bf39ded 100644
--- a/apps/planner/app/root.tsx
+++ b/apps/planner/app/root.tsx
@@ -1,5 +1,6 @@
-import { Links, Meta, Outlet, Scripts, ScrollRestoration } from "react-router";
+import { Links, Meta, Outlet, Scripts, ScrollRestoration, isRouteErrorResponse } from "react-router";
 import type { LinksFunction } from "react-router";
+import type { Route } from "./+types/root";
 import stylesheet from "@trails-cool/ui/styles.css?url";
 
 export const links: LinksFunction = () => [{ rel: "stylesheet", href: stylesheet }];
@@ -25,3 +26,31 @@ export function Layout({ children }: { children: React.ReactNode }) {
 export default function App() {
   return <Outlet />;
 }
+
+export function ErrorBoundary({ error }: Route.ErrorBoundaryProps) {
+  if (isRouteErrorResponse(error)) {
+    return (
+      <div className="flex h-full items-center justify-center">
+        <div className="text-center">
+          <h1 className="text-4xl font-bold text-gray-900">{error.status}</h1>
+          <p className="mt-2 text-gray-600">
+            {error.status === 404 && "Page not found"}
+            {error.status === 503 && "Service temporarily unavailable"}
+            {error.status !== 404 && error.status !== 503 && (error.statusText || "Something went wrong")}
+          </p>
+        </div>
+      </div>
+    );
+  }
+
+  return (
+    <div className="flex h-full items-center justify-center">
+      <div className="text-center">
+        <h1 className="text-4xl font-bold text-gray-900">Error</h1>
+        <p className="mt-2 text-gray-600">
+          {error instanceof Error ? error.message : "An unexpected error occurred"}
+        </p>
+      </div>
+    </div>
+  );
+}
diff --git a/packages/db/src/index.ts b/packages/db/src/index.ts
index df18f2e..26f84fa 100644
--- a/packages/db/src/index.ts
+++ b/packages/db/src/index.ts
@@ -20,23 +20,22 @@ export type Database = ReturnType<typeof createDb>;
  */
 export function withDb<T>(handler: () => Promise<T>): Promise<T> {
   return handler().catch((error) => {
-    // Re-throw React Router responses (redirects, data() throws)
-    // Check for Response, ErrorResponseImpl, or anything with a status property
+    // Re-throw anything that looks like a React Router response:
+    // - Response (redirects)
+    // - ErrorResponseImpl from data() throws (has status + data)
     if (
       error instanceof Response ||
-      (error && typeof error === "object" && "status" in error && "data" in error)
+      (error != null && typeof error === "object" && "status" in error)
     ) {
       throw error;
     }
 
-    // Any other error from a DB-wrapped handler is treated as DB unavailable
+    // Database error — throw as a 503 that the error boundary will catch
     const message = error instanceof Error ? error.message : String(error);
     console.error("[withDb] Database error:", message);
 
-    throw new Response(JSON.stringify({ error: "Database unavailable" }), {
-      status: 503,
-      headers: { "Content-Type": "application/json" },
-    });
+    // Use the same shape as data() throw so isRouteErrorResponse works
+    throw new Response("Database unavailable", { status: 503, statusText: "Service Unavailable" });
   });
 }