Good question. They both use npub authentication, and have become a standard for nostr media hosting. A big difference is that Blossom is a standard that allows a blossom comparable server to instantly integrate with the client making it easier for clients to interoperable with media servers, and users to create Blossom servers that instantly can integrate with clients. While nip96 focuses on one aspect of authentication, Blossom is more holistic encompassing more than just npub authentication. nostr:npub137c5pd8gmhhe0njtsgwjgunc5xjr2vmzvglkgqs5sjeh972gqqxqjak37w wrote a great blog going into more detail about our Blossom implementation.

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