Just read trough entire thread. As a developer myself I can tell this was one of the best threads (well most fun for me at least...) I saw in quite some time. Really good job making all this information open for everyone that might need it in the future.
I'll share parts of the code. Maybe it will be helpful to someone too.
Anyways not sure what your current application structure is, but I'm a big fan of Go and NodeJS. Try the microservices approach, it will be worth it long term, trust me.
This is exactly what I do. Each part of the system is microservice.
Keep up the good work !
Thank you!