diff --git a/bin/compile b/bin/compile
index ab320a7c7ac7489af034a94508f7e0fafd901aac..bba2431e2d581f0ad128cc7bd0971c405d717519 100755
--- a/bin/compile
+++ b/bin/compile
@@ -37,6 +37,7 @@ export BPWATCH_STORE_PATH=$CACHE_DIR/bpwatch.json
 BUILDPACK_VERSION=v28
 
 # Support Anvil Build_IDs
+[ ! "$SLUG_ID" ] && SLUG_ID="defaultslug"
 [ ! "$REQUEST_ID" ] && REQUEST_ID=$SLUG_ID
 
 # Sanitizing environment variables.