From Revolt Wiki

Harmony was an open source federated chat protocol, the developers do not intend to pursue it anymore[1].

Development ceased around the 11th of February 2022[2].

The harmonyapp.io domain expired on the 18th of December 2022.

Notable Sub-projects
Project Description
Challah A Qt/KF5 client for Harmony
ilo toki A terminal client for Harmony
Loqui Harmony client made with Rust using the egui GUI library
Tempest A web client for Harmony written in Vue
Marcato A Swift-based server for Harmony
schzero A Rust server for Harmony, built using hyper
legato Scalable server implementation for the Harmony protocol (written in Go)


hRPC is an RPC system using protocol buffers over HTTP and WebSockets[3].

An article was posted in November 2021 explaining the goals and idea behind hRPC[4].