diff --git a/Dockerfile b/Dockerfile
index f85c2b2..c4c27ff 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -50,6 +50,11 @@ RUN test -n "$NEXT_PUBLIC_PB_URL" \
 ENV NEXT_TELEMETRY_DISABLED=1
 ENV NODE_ENV=production
 
+# The commit being built, supplied by Ship. Declared late so the layers above
+# stay cached; it is empty for builds that do not pass it.
+ARG NEXT_PUBLIC_APP_COMMIT
+ENV NEXT_PUBLIC_APP_COMMIT=${NEXT_PUBLIC_APP_COMMIT}
+
 # `next build --webpack` is deliberate: @ducanh2912/next-pwa is Webpack-only
 # and is what generates public/sw.js + public/workbox-*.js. Dropping the flag
 # silently ships an app with no service worker and no offline install.
diff --git a/app/layout.tsx b/app/layout.tsx
index 53585d0..e913a17 100644
--- a/app/layout.tsx
+++ b/app/layout.tsx
@@ -2,6 +2,7 @@ import "./globals.css";
 import type { Metadata, Viewport } from "next";
 import { ThemeProvider } from "@/components/ThemeProvider";
 import { SessionLifecycle } from "@/components/auth/SessionLifecycle";
+import { BuildStamp } from "@/components/BuildStamp";
 
 export const metadata: Metadata = {
   title: "Mega Plant Dashboard",
@@ -45,7 +46,7 @@ export default function RootLayout({ children }: { children: React.ReactNode })
         />
       </head>
       <body className="min-h-screen">
-        <ThemeProvider><SessionLifecycle />{children}</ThemeProvider>
+        <ThemeProvider><SessionLifecycle />{children}<BuildStamp /></ThemeProvider>
       </body>
     </html>
   );
diff --git a/components/BuildStamp.tsx b/components/BuildStamp.tsx
new file mode 100644
index 0000000..be90fc3
--- /dev/null
+++ b/components/BuildStamp.tsx
@@ -0,0 +1,32 @@
+/**
+ * The commit this build came from, as a faint mark in the corner.
+ *
+ * `NEXT_PUBLIC_APP_COMMIT` is set by Ship (the Forgejo Desktop app) when it
+ * builds the image. A build made any other way has no value, so nothing is
+ * rendered. It never takes a click and is nearly transparent.
+ */
+export function BuildStamp() {
+  const commit = process.env.NEXT_PUBLIC_APP_COMMIT;
+  if (!commit) return null;
+
+  return (
+    <div
+      aria-hidden="true"
+      title={`Build ${commit}`}
+      style={{
+        position: "fixed",
+        right: 6,
+        bottom: "calc(env(safe-area-inset-bottom, 0px) + 3px)",
+        zIndex: 2147483647,
+        fontSize: 9,
+        lineHeight: 1,
+        fontFamily: "ui-monospace, SFMono-Regular, Menlo, monospace",
+        opacity: 0.3,
+        pointerEvents: "none",
+        userSelect: "none",
+      }}
+    >
+      {commit}
+    </div>
+  );
+}