Is there any recommend (or fast) python web server framework

I currently building an online judge system. I use django and django-rest to build to restful api backend, and use it to handle submission CRUD something like that.

After the django received a submission, it will pass it to Celery, and in the Celery task, it will make a request to my judge server.

And my problem is which python web framework should I choose to implement this judge server.

<client> → <django rest> → <Celery> → <!!! judge server !!!> → <judger sandbox>

Because I have a sandbox library which can be import in python like this

import _judger
_judger.run( bash command or something like that here )

And it will be multiprocess inside each requeste, because each submission has multiple test case to execute.

And I need a reliable and fast (less overhead on networking) framework to build a server to wrap the sandbox, is there any good suggestion? Thanks a lot.