diff --git a/Dockerfile b/Dockerfile
index 2d81464..0cdd292 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,5 +15,6 @@ COPY --from=dependencies-env /app/node_modules /app/node_modules
 COPY --from=build-env /app/build /app/build
 COPY --from=build-env /app/public /app/public
 WORKDIR /app
+ENV PORT=4000
 # there is a DOMAINS env with comma separated allowed domains for image processing
-CMD ["PORT=4000", "npm", "run", "start"]
+CMD ["npm", "run", "start"]