mattn/efm-langserver

Health v2 · maintenance only

Adoption not part of the score

1553 stars · 62 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

efm-langserver is a general-purpose Language Server Protocol server written in Go that acts as a bridge between editors and external linters/formatters. It invokes configured command-line tools, translates their output into LSP diagnostics and formatting responses, and works with any editor that supports LSP.

Use cases

• add linting diagnostics to any language in vim or neovim via LSP
• use external formatters like yapf or LuaFormatter from my editor
• get linter and formatter support in editors without native LSP plugins
• wire arbitrary CLI tools into LSP diagnostics
• set up efm-langserver with coc.nvim or Eglot
• format files on save using existing command-line tools

When to choose

• you use an LSP-capable editor and want diagnostics/formatting from existing linters and formatters
• your language has no dedicated language server but has CLI lint/format tools
• you want one configurable proxy for many languages' tools

When to avoid

• a dedicated language server exists for your language and provides richer features
• you expect built-in linters/formatters — efm bundles none
• you need full IDE semantics like completion or go-to-definition

Facets

cli-tool · maturity active

linter formatter developer-tools developer-tools text-editors windows cross-platform cli language-server-protocol lsp editor-integration go command-line linux macos

Member repositories

For agents

markdown · JSON · MCP: product_card(name="mattn/efm-langserver")