diff --git a/docker/backend/Dockerfile b/docker/backend/Dockerfile
index 5e79a48ca..563e15917 100644
--- a/docker/backend/Dockerfile
+++ b/docker/backend/Dockerfile
@@ -6,16 +6,24 @@ FROM ${FROM_IMG}:${FROM_TAG}
 ENV LANG=de_DE.UTF-8
 
 # compile-time dependencies
-RUN apt-get -y update && apt-get install -y libpq-dev libsodium-dev
+RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
+--mount=type=cache,target=/var/lib/apt,sharing=locked \
+apt-get -y update && apt-get install -y libpq-dev libsodium-dev
 # RUN apt-get -y update && apt-get -y install llvm
 # RUN apt-get -y update && apt-get -y install g++ libghc-zlib-dev libpq-dev libsodium-dev pkg-config
 # RUN apt-get -y update && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends tzdata
-RUN apt-get -y update && apt-get install -y --no-install-recommends locales locales-all
+RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
+--mount=type=cache,target=/var/lib/apt,sharing=locked \
+apt-get -y update && apt-get install -y --no-install-recommends locales locales-all
 
 # run-time dependencies for uniworx binary
-RUN apt-get -y update && apt-get -y install fonts-roboto
+RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
+--mount=type=cache,target=/var/lib/apt,sharing=locked \
+apt-get -y update && apt-get -y install fonts-roboto
 # RUN apt-get -y update && apt-get -y install pdftk
-RUN apt-get -y update && apt-get -y install texlive-latex-recommended texlive-luatex texlive-plain-generic texlive-lang-german texlive-lang-english
+RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
+--mount=type=cache,target=/var/lib/apt,sharing=locked \
+apt-get -y update && apt-get -y install texlive-latex-recommended texlive-luatex texlive-plain-generic texlive-lang-german texlive-lang-english
 
 # locally these two should be identical, so that compilation results are written out into the file dir.
 # in CI-pipelines these two should be different, so that the container caches the compilation results.