diff --git a/compose.override.yaml b/compose.override.yaml
index 9728a19..1dbe927 100644
--- a/compose.override.yaml
+++ b/compose.override.yaml
@@ -56,9 +56,12 @@ services:
       CHOKIDAR_USEPOLLING: "true"
     # Marks the service healthy only once Vite is actually serving — the e2e
     # runner waits on this (condition: service_healthy) to avoid racing startup.
-    # start_period covers the slow first boot (global npm install + npm install).
+    # Use 127.0.0.1, NOT localhost: the container resolves localhost to ::1
+    # (IPv6) first, but Vite binds 0.0.0.0 (IPv4 only) → an IPv6 probe is
+    # refused and the container never goes healthy. start_period covers the
+    # first boot (npm install of the app deps).
     healthcheck:
-      test: ["CMD", "wget", "-qO-", "http://localhost:5173/"]
+      test: ["CMD", "wget", "-qO-", "http://127.0.0.1:5173/"]
       interval: 5s
       timeout: 3s
       retries: 5