diff --git a/Dockerfile b/Dockerfile
index c53bf0c..3e66cc9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,7 +6,7 @@ ENV DEBIAN_FRONTEND=noninteractive
 RUN sed -i "s|deb.debian.org|${APT_MIRROR}|g; s|security.debian.org|${APT_MIRROR}|g" /etc/apt/sources.list.d/debian.sources
 
 RUN apt-get update \
-    && apt-get install -y --no-install-recommends python3 python3-pip ca-certificates git \
+    && apt-get install -y --no-install-recommends python3 python3-pip python3-venv ca-certificates git \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
diff --git a/docker/start.sh b/docker/start.sh
index 1b5f502..86a5d2a 100644
--- a/docker/start.sh
+++ b/docker/start.sh
@@ -18,7 +18,11 @@ else
 fi
 
 echo "[start] installing backend dependencies"
-python3 -m pip install --no-cache-dir -r "${WORKTREE_DIR}/backend/requirements.txt"
+VENV_DIR="${WORKTREE_DIR}/.venv"
+if [ ! -x "${VENV_DIR}/bin/python" ]; then
+  python3 -m venv "${VENV_DIR}"
+fi
+"${VENV_DIR}/bin/pip" install --no-cache-dir -r "${WORKTREE_DIR}/backend/requirements.txt"
 
 echo "[start] installing frontend dependencies and building"
 cd "${WORKTREE_DIR}/frontend"
@@ -27,7 +31,7 @@ npm run build
 
 echo "[start] launching backend:${BACKEND_PORT} and frontend:${FRONTEND_PORT}"
 cd "${WORKTREE_DIR}/backend"
-python3 app.py &
+"${VENV_DIR}/bin/python" app.py &
 BACKEND_PID=$!
 
 cd "${WORKTREE_DIR}/frontend"