Supertestnet is back with more fun bitcoin things and I really like this:
This is a tool for emulating bitcoind by getting block data from electrum servers, with two demos in the form of a webapp and a desktop app.
Demo version: https://supertestnet.github.io/node_faker
Why Did I Make This?
For two main reasons. One is that when working on some of my other projects I occasionally look for a way to interact with bitcoind programatically in the browser, but I find it hard to keep a node running; I run all my nodes on my laptop, which is usually turned off, so when I start them up, they have a lot of syncing to do, which makes me wait before doing whatever it is I wanted to do. This tool lets me emulate a fully synced node and test my apps against that, with confidence that my apps might not need much modification to work with "real" bitcoin nodes.