You need to be comfortable with object oriented as well as functional programming.
A basic grasp of C# is helpful, but we feel the code will be legible to developers familiar with Java and other C-based languages.
No mathematical knowledge is required. We will not cover cryptography beyond the bare minimum you need to know to make a secure service.
You don’t need to have deep knowledge of Bitcoin.
Bitcoin Core - Ideally you have it, but you can just proceed without it.
Tip: If disk space is an issue, consider running Bitcoin Core in pruning mode. It is practically the same as a full node (including security), except it throws away some of the old history.