diff --git a/src/routes/join/[code]/+page.ts b/src/routes/join/[code]/+page.ts
new file mode 100644
index 0000000..fabe7ce
--- /dev/null
+++ b/src/routes/join/[code]/+page.ts
@@ -0,0 +1,2 @@
+// A room is known only at runtime: the fallback shell serves it and the client reads the code from the address.
+export const prerender = false;