diff --git a/Dockerfile b/Dockerfile
index 49868ad..edda3ea 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -92,6 +92,7 @@ COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV}/rel/putzplan ./
 USER nobody
 
 ENV DATABASE=${DATABASE}
+EXPOSE 4000
 
 # If using an environment that doesn't automatically reap zombie processes, it is
 # advised to add an init process such as tini via `apt-get install`