fmsg is a message definition and protocol intended as an alternative to email and IM apps. Like email it's distributed – anyone can host a server for their domain. Unlike email, messages are binary, verifiable by all peers, and linked into a DAG using cryptographic hashes. Sender verification and message integrity are built into the protocol, so you get what email needs SPF/DKIM/DMARC for out of the box.The host implementation (fmsgd) is written in Go. There's a Docker compose setup to get a full stack running in minutes: https://github.com/markmnl/fmsg-docker
The spec is nearing v1.0: https://github.com/markmnl/fmsg — would love feedback. Send me a fmsg at @[email protected]