Similarly, we ended up doing the same. Boring CRUD/CMS stuff is all in Django. That's 90% of our codebase and by far the most important. Our "user scale" endpoints are all implemented in Lua in NGINX and just read/write to Redis and data changes go into SQS and processed by Celery back in the Django app. It scales phenomenally well and we don't lose any of the great things about developing all of our core biz-critical stuff in Django.