hpfeeds-broker
Originally written for python2 and gevent, the original hpfeeds broker has been ported to python3 and asyncio. It’s gained prometheus integration for monitoring. If you only have a small-medium number of user accounts you can use a Kubernetes Secret resource to manage access control.
HPFBroker
HPFBroker is a hpfeeds broker written in go by @d1str0. It has a webserver GUI for managing channels, users and passwords. It has an API for use as a microservice.
Tentacool
Tentacool is a C++ implementation of a hpfeeds broker capable of 65k messages / second (as measured in 2014). As well as simple flat file authentication configuration it can use mongo as its auth store.