diff --git a/builder/build.sh b/builder/build.sh
index 4a15394..6603cdd 100755
--- a/builder/build.sh
+++ b/builder/build.sh
@@ -119,6 +119,14 @@ if curl --silent --fail "${CADDY_API}/config/" >/dev/null 2>&1; then
     UPSTREAM="${CONTAINER_IP}:${PORT}"
     log "Updating Caddy: ${APP_ID}.${DOMAIN_SUFFIX} → ${UPSTREAM}"
 
+    # Discover actual server name (Caddyfile adapter names it 'srv0', not 'hiy').
+    CADDY_SERVER=$(curl --silent "${CADDY_API}/config/apps/http/servers/" 2>/dev/null | \
+        python3 -c "import sys,json; d=json.load(sys.stdin); print(next(iter(d)))" 2>/dev/null || true)
+    if [ -z "$CADDY_SERVER" ]; then
+        log "WARNING: Could not discover Caddy server name; skipping route update."
+    else
+    ROUTES_URL="${CADDY_API}/config/apps/http/servers/${CADDY_SERVER}/routes"
+
     ROUTE_JSON=$(cat <<EOF
 {
     "match":  [{"host": ["${APP_ID}.${DOMAIN_SUFFIX}"]}],
@@ -127,7 +135,7 @@ if curl --silent --fail "${CADDY_API}/config/" >/dev/null 2>&1; then
 EOF
 )
     # Upsert the route for this app.
-    ROUTES=$(curl --silent --fail "${CADDY_API}/config/apps/http/servers/hiy/routes" 2>/dev/null || echo "[]")
+    ROUTES=$(curl --silent --fail "${ROUTES_URL}" 2>/dev/null || echo "[]")
     # Remove existing route for the same host, rebuild list, keep dashboard as catch-all.
     UPDATED=$(echo "$ROUTES" | python3 -c "
 import sys, json
@@ -154,7 +162,7 @@ print(json.dumps(routes))
     set +e
     CADDY_RESP=$(curl --silent --show-error \
         --write-out "\nHTTP_STATUS:%{http_code}" \
-        "${CADDY_API}/config/apps/http/servers/hiy/routes" \
+        "${ROUTES_URL}" \
         --header "Content-Type: application/json" \
         --request PATCH \
         --data "$UPDATED" 2>&1)
@@ -165,6 +173,7 @@ print(json.dumps(routes))
         log "WARNING: Caddy update failed (app is running; fix routing manually)."
         log "Caddy response: ${CADDY_RESP}"
     fi
+    fi  # end: CADDY_SERVER not empty
 else
     log "Caddy admin API not reachable; skipping route update."
     log "Container ${CONTAINER_NAME} is running on port ${PORT} but not publicly routed."