lspd

LSP multiplexer daemon for sharing language server instances across multiple editors.

This project is Bun/TypeScript-based (it previously had a Rust implementation, which has been removed).

Problem

Two failure modes that lspd handles:

1. If you open multiple editor instances on the same project (multiple Neovim windows, OpenCode + Neovim, etc.), each client usually spawns its own language server process. For heavier servers like tsgo, this wastes a lot of CPU and memory.
2. Servers like oxlint and tsgo are happiest when scoped to one config file (.oxlintrc.json, tsconfig.json). Running a single instance over a large monorepo conflates configs and can be slow. Splitting per config keeps state small and per-package settings honored.

Solution

lspd sits between your editor(s) and the language server.

• For oxlint and tsgo (default): one server process per (nearest config file, server) pair. Files in packages/foo/ use the LSP rooted at packages/foo/; files in packages/bar/ use a separate LSP. Children are spawned lazily as you open files.
• For other servers (or with --single-process): one server process per (projectRoot, serverName) pair, multiplexed to all editors.

Either way, multiple editor clients can share the same daemon.

Features

• Per-manifest routing for oxlint (.oxlintrc.json) and tsgo (tsconfig.json, jsconfig.json)
• Shared LSP instances across editor clients
• Automatic lifecycle (daemon starts on first connection; exits after last client disconnects)
• Binary discovery (prefers node_modules/.bin, with env overrides)
• Request id translation (prevents collisions across multiple clients)
• Diagnostics bridging for mixed clients
  • If a client doesn't support pull diagnostics (textDocument/diagnostic), the mux bridges pull->push using textDocument/publishDiagnostics.

Installation

This package requires bun to be installed (the CLI is a small Node wrapper that spawns Bun).

npm install -g lspd
# or
bun add -g lspd

Usage

Connect (used by editors)

lspd connect tsgo --project /path/to/project
lspd connect oxlint --project /path/to/project

# Force one process for the whole project (disables per-manifest routing):
lspd connect oxlint --project /path/to/project --single-process

Manage daemons

lspd ps
lspd ps --json

lspd kill tsgo --project /path/to/project
lspd kill oxlint --project /path/to/project --single-process
lspd kill --all

lspd prune

Your editor should start lspd connect <server> and speak LSP over stdin/stdout.

Neovim example

-- instead of: cmd = { "tsgo", "--lsp", "-stdio" }
cmd = { "lspd", "connect", "tsgo", "--project", vim.loop.cwd() }

Configuration

Environment variables:

• LSPD_TSGO_BIN=/absolute/path/to/tsgo
• LSPD_OXLINT_BIN=/absolute/path/to/oxlint

How it works (high-level)

• lspd connect <server> ensures a daemon for (projectRoot, server) is running.
• The daemon listens on a Unix domain socket under:
  • ~/.cache/lspd/daemons/<id>/daemon.sock
• All connected editor clients are multiplexed to that daemon.
• Inside the daemon:
  • For oxlint / tsgo: each inbound message is routed by its textDocument.uri to a child LSP whose cwd is the file's nearest manifest dir (.oxlintrc.json or tsconfig.json). Children are spawned lazily. Files outside any manifest fall back to a child rooted at --project.
  • For other servers (or with --single-process): one shared child handles everything.
• Request ids are translated to avoid collisions; server-initiated requests are forwarded to the primary client and routed back to the originating child.

Caveats for per-manifest mode

• Cross-config requests (e.g. tsgo find references across packages with separate tsconfig.jsons) only see the file's own subproject. If your monorepo relies on TS project references for cross-package navigation, use --single-process for tsgo.
• workspace/symbol and similar workspace-wide queries are best-effort: they go to the --project fallback child only.

Development

bun test

Notes:

• The smoke tests use test-fixtures/proj and will run bun install there as needed.
• The tsgo smoke test may build tsgo from source if the prebuilt binary hangs, which requires git, go, and network access.

License

MIT (see LICENSE).