NIP-60
Cashu wallets
NIP-60 defines how Cashu wallet information can be represented on Nostr. It supports ecash wallets that can move between compatible apps.
NIP-60 is one of the small agreements that lets different Nostr apps understand the same kind of activity. In everyday terms, it is like agreeing on the shape of a form: once everyone uses the same form for cashu wallets, people can move between apps without losing the meaning of what they created.
Read more in the official 60.md NIP document.