nostr:npub1l2vyh47mk2p0qlsku7hg0vn29faehy9hy34ygaclpn66ukqp3afqutajft, the dev behind zapstr also published https://ndk.fyi/ , a Nostr client toolkit. Pablo is too prolific 😅

If you want to build on Nostr, you can have a look at NDK