I see, but in that case it still depends on a special email service. My project is Chuchu, and I plan to add third-party logins.

GitHub

GitHub - chuchu-nostr/chuchu: A decentralized content subscription platform based on the Nostr protocol

A decentralized content subscription platform based on the Nostr protocol - chuchu-nostr/chuchu

My idea is to derive a unique private key from: 1)the unique secret obtained from third-party login, and 2)a user-provided passcode, so that no dedicated server is needed.