Thank you! I'm an application dev (primarily C#/.NET), so I went with what I know.

I use Voltage for Lightning Node infrastructure, a .NET and Azure hosted webjob for syncing network data, MongoDB for persistence, Azure Blob Storage for graph storage, and Azure webapp (C#/.NET) for hosting the main explorer.

The Lightning Lab team has made some great gRPC APIs available for pulling data from a lightning node.

The biggest challenge for me is understanding all of the network data - what do things like HTLCs or Parts per Million all mean in both a technical and business context. I'm still ramping up here, and posting at a '101' level as I learn more and run examples on my own lightning nodes (which is great with Voltage): https://docs.exponentiallayers.com/lightning-network-concepts/lightning-network-overview

And I'll get some links up soon of various resources and threads that have been helpful.

As for open source, I hope to carve out pieces to make publicly available in the future. In all honesty though, my hope is to start charging for new features shortly so that I can cover all of my hosting costs (Azure, Mongo, Voltage, WebFlow, etc - it adds up fast) and cover some level of my basic living expenses. I left my full time job to explore Bitcoin and the space in general because it is so interesting, so I need some way to cover my expenses to be able to do this indefinitely. So expect to see some paid features soon!