collabd - editor-agnostic collaborative editing daemon

daemon + thin adapters architecture. daemon handles yjs crdt, adapters just hook buffer events and apply remote changes.

status

working:

daemon with room-based sessions
multi-peer sync (tested with 2+ clients)
vim9 adapter with live buffer sync
proper crdt diffing (not delete-all-insert-all)
integration tests for concurrent edits

not yet:

cursor/selection sync (awareness protocol stubbed but unused)
other editor adapters (helix, kakoune, zed)
persistence (rooms are ephemeral)
reconnection handling

stack

bun runtime
yjs for crdt
websocket transport
vim9script adapter (with bun bridge since vim cant do websocket)

running

just dev          # daemon on :4040
bun test          # unit tests
just check        # biome lint

vim adapter usage

requires Vim 9.0+ (uses vim9script)

:source adapters/vim/collab.vim
:CollabJoin roomname
:CollabLeave
:CollabStatus

the vim plugin spawns adapters/vim/bridge.ts which handles yjs and speaks json lines to vim via channels.

protocol

daemon speaks json over websocket at /ws

client -> server: { type: "join", room: "name" } { type: "leave" } { type: "update", data: [...] } // yjs update bytes

server -> client: { type: "sync", data: [...] } // full yjs state on join { type: "update", data: [...] } // remote changes { type: "peers", count: N }

key files

src/index.ts - websocket server, room routing
src/session.ts - yjs doc per room, peer management
src/protocol.ts - message types
adapters/vim/bridge.ts - bun process vim spawns
adapters/vim/collab.vim - vim9script plugin

adding new editor adapters

each adapter needs:

hook buffer change events
send changes to daemon as yjs updates (or use a bridge like vim does)
receive remote updates and apply to buffer
optionally show peer cursors

see NOTES.txt for cell-grid vs text-crdt mode discussion. see docs/ for full research and architecture breakdown.

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