diff --git a/build-static.sh b/build-static.sh
index 529c3cbba..b7fb17395 100755
--- a/build-static.sh
+++ b/build-static.sh
@@ -74,12 +74,15 @@ if [ -n "${CLEAN}" ]; then
 	go clean -cache
 fi
 
+cache_key="${PHP_VERSION}-${PHP_EXTENSIONS}-${PHP_EXTENSION_LIBS}"
+
 # Build libphp if necessary
-if [ -f "dist/static-php-cli/buildroot/lib/libphp.a" ]; then
+if [ -f dist/cache_key ] && [ "$(cat dist/cache_key)" = "${cache_key}" ] && [ -f "dist/static-php-cli/buildroot/lib/libphp.a" ]; then
 	cd dist/static-php-cli
 else
 	mkdir -p dist/
 	cd dist/
+	echo -n "${cache_key}" >cache_key
 
 	if [ -d "static-php-cli/" ]; then
 		cd static-php-cli/
diff --git a/static-builder.Dockerfile b/static-builder.Dockerfile
index 269b9bad1..74583a322 100644
--- a/static-builder.Dockerfile
+++ b/static-builder.Dockerfile
@@ -106,5 +106,4 @@ COPY --link caddy caddy
 COPY --link internal internal
 
 RUN --mount=type=secret,id=github-token GITHUB_TOKEN=$(cat /run/secrets/github-token) ./build-static.sh && \
-	rm -Rf dist/static-php-cli/source/* && \
-    rm dist/static-php-cli/buildroot/lib/libphp.a
+	rm -Rf dist/static-php-cli/source/*