diff --git a/Dockerfile b/Dockerfile
index bbd7743b..b7bbc499 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 # Build stage
 ARG TAG
-FROM cs50/cli:${TAG} as builder
+FROM cs50/cli:${TAG} AS builder
 ARG DEBIAN_FRONTEND=noninteractive