For development-related questions — bugs, feature requests, API specifics — the best place is the GitHub issue tracker of the relevant project, such as Nanopub Registry, Nanopub Query, Nanodash, or one of the client libraries.

For broader questions, discussions, or simply getting in touch with the community, several channels listed at nanopub.net/contact are active: a public Matrix chat, the nanopub-users mailing list, the @nanopub Mastodon account, and the association@nanopub.net email address of the Nanopublication Association.