diff --git a/Dockerfile b/Dockerfile
index e128c14..76752e6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -60,6 +60,7 @@ RUN echo "auth requisite pam_deny.so" >> /etc/pam.d/su && \
 
 # Install the jupiterhub proxy
 RUN pip3 install \
+    jsonschema'[format,format-nongpl]' \
     jupyterhub \
     jupyterlab \
     jupyter-rsession-proxy \