diff --git a/Dockerfile b/Dockerfile
index 96e8fa9..824d1a4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -20,7 +20,7 @@ FROM base AS build
 
 # Install packages needed to build gems and node modules
 RUN apt-get update -qq && \
-    apt-get install --no-install-recommends -y build-essential curl git libpq-dev libvips node-gyp pkg-config python-is-python3
+    apt-get install --no-install-recommends -y build-essential curl git libpq-dev libvips libyaml-dev node-gyp pkg-config python-is-python3
 
 # Install JavaScript dependencies — Node version is read from .node-version
 COPY .node-version /tmp/.node-version