Language servers
Helix has built-in support for the Language Server Protocol, providing IDE-like features — diagnostics, completion, goto-definition, rename and more, for any language that has a server configured. Language servers are separate programs you install yourself: the language support page lists which languages ship with a server configured, and the language server configuration wiki has per-server installation notes.
Run hx --health <language> to check whether Helix found the configured server
for a language. After changing a server's configuration, :lsp-restart reloads
it and :lsp-stop stops it; :lsp-workspace-command runs a command the server
exposes for the workspace.
Features
Most features are bound by default (see the keymap); the relevant keys are listed below.
| Feature | Default key / command |
|---|---|
| Diagnostics — shown inline and in the gutter | navigate with [d / ]d; Space-d / Space-D open the document / workspace pickers |
| Completion | automatic while typing; Ctrl-x triggers it manually |
| Hover documentation | Space-k |
| Signature help (parameter hints) | automatic while typing arguments |
| Goto definition / declaration / type / references / implementation | gd / gD / gy / gr / gi |
| Rename symbol | Space-r |
| Code actions | Space-a |
| Document / workspace symbols | Space-s / Space-S |
| Format document | :format, or set auto-format to format on save |
| Inlay hints | enable with display-inlay-hints (see below) |
Configuration
The [editor.lsp] section of config.toml
toggles LSP behaviour — display-inlay-hints, auto-signature-help,
auto-document-highlight, snippets, and enable to disable LSP entirely. How
much diagnostic detail is shown inline at the cursor is configured separately in
[editor.inline-diagnostics].
Which server(s) a language uses, the server's command and arguments, and any
language-specific settings are configured in languages.toml (see
Language Server configuration). A
language may use several servers:
for each request the first server in the list that supports it is used, and a
server's features can be limited with only-features / except-features.