There’s Briar: https://briarproject.org/ and Manyverse which uses the Scuttlebutt Protocol: https://manyver.se which are close but not perfect. Source: about 1 year ago

Manyverse is cross-platform and it's the main desktop app nowadays: https://manyver.se The Scuttlebutt.nz website hasn't been kept up-to-date. SSB's development is also decentralized, so this doesn't mean that everything moves forward in unison, so depending on who you ask, Scuttlebutt.nz is not the official frontpage. - Source: Hacker News / over 1 year ago

Manyverse (version 0.2210.3-beta-fdroid): A social network off the grid. Source: over 1 year ago

This looks pretty interesting. Do you know how it is different from similar systems that use the SSB protocol, like Manyverse for example? Source: over 1 year ago

I really look forward to interfaces that let me use my own index of data from my network. Manyverse[1] and Iris[2] are good examples of apps that will enable this more in the future. I just want to search “harry potter” and see everything my friends have written about it. If I follow some institutions or encyclopedias, I should also see what they write about it. And I should be able to choose which... - Source: Hacker News / almost 2 years ago

Use https://bridgefy.me for offline communication. Source: over 1 year ago

Have a look at https://bridgefy.me/, this may be interesting to you. Source: over 1 year ago

5. There's another company called Bridgefy https://bridgefy.me/ that built a chat app used in some of the Hong Kong protests. - Source: Hacker News / almost 2 years ago

Bridgefy is designed to work on local Bluetooth (max about 100m) during natural disasters, a protest, at large events, at schools, etc. It will create a mesh network, so one or more other peers can help transmit messages further. See https://bridgefy.me/. Source: over 2 years ago

How about offline P2P mesh bluebottle chat? Check out this one used by protestors https://bridgefy.me/. Source: over 2 years ago