fmsg: An open, binary, distributed messaging protocol

fmsg enters a crowded field of communication tools with a refreshingly pragmatic goal: returning to the 'open distributed promise' of the early internet. While modern messaging has bifurcated into centralized silos (WhatsApp, Telegram) or complex federated layers (Matrix), fmsg attempts a middle path. It adopts the @user@domain addressing scheme of email but strips away the legacy overhead of SMTP and the inefficiency of Base64-encoded attachments, opting instead for a compact binary format that prioritizes wire efficiency. Technically, the standout feature is the use of a DAG to link messages. By hashing previous messages into the current one, the protocol creates a verifiable chain of conversation that serves two purposes: it naturally forms threads and provides a cryptographic signal to filter spam based on previous participation. The addition of an automatic 'challenge-back' mechanism during the handshake is a clever attempt to solve the sender verification problem without requiring the labyrinthine setup of SPF, DKIM, and DMARC. However, the project is currently in its infancy. While the specification is nearing v1.0 and the Go implementation is solid, the ecosystem is sparse. With only a CLI tool and a web API available, the barrier to entry remains high for non-developers. The success of any protocol depends entirely on the network effect; until a diverse set of clients emerges, fmsg remains a compelling technical exercise rather than a viable alternative to Gmail or Signal. This is for the builders and the sovereignty-obsessed. If you are tired of your data sitting in a corporate black box and you have the technical appetite to run your own host, fmsg is a sophisticated foundation. It respects the engineer's desire for efficiency and the user's desire for control, provided they are willing to help build the house they intend to live in.