---
title: "Language server · MacMelon"
description: "A language server powers autocomplete and errors in editors such as VS Code and Cursor. TypeScript's tsserver is one. Long sessions can make them large."
url: "https://macmelon.com/glossary/language-server"
---

# Language server

The background process that gives a code editor autocomplete, go-to-definition, and error checking for a language.

Editors such as VS Code, Cursor, and Windsurf do not understand each language themselves. They run a language server for it, such as tsserver for TypeScript, pyright for Python, or rust-analyzer for Rust, and ask it questions as you type. Each open project can have its own, inside the editor's extension host.

Language servers can grow large over a long session. Stopping one is safe in the sense that the editor starts a fresh one automatically, with a short pause in autocomplete. [Sentinely](https://macmelon.com/apps/sentinely) offers that restart when a language server is holding a lot of memory. See [When VS Code or Cursor slows your Mac](https://macmelon.com/use-cases/vs-code-or-cursor-slowing-your-mac).

## Apps

[No more Force Quit in the middle of a build. ### Sentinely](https://macmelon.com/apps/sentinely)

## Related guides

[### How to find what's slowing down your Mac](https://macmelon.com/guides/how-to-find-what-is-slowing-down-your-mac)

## Related use cases

[### When VS Code or Cursor slows your Mac](https://macmelon.com/use-cases/vs-code-or-cursor-slowing-your-mac)

## Related terms

[A helper program that gives an AI app access to a tool or data source, often running as a separate process on your Mac. ### MCP server](https://macmelon.com/glossary/mcp-server)[The memory macOS charges to a process, including memory it has compressed. Sentinely's unit for estimates and receipts. ### Memory footprint](https://macmelon.com/glossary/memory-footprint)[The folder where a JavaScript project keeps its installed dependencies. ### node\_modules](https://macmelon.com/glossary/node-modules)