Open source language-server projects

Every project in the registry tagged language-server, ranked by real GitHub adoption.

projects 3 combined stars ★ 12K refresh nightly
01 pyrefly ★ 7.0K

A fast type checker and language server for Python

last push2 hours ago languageRust licenseMIT
02 marksman ★ 3.4K

Write Markdown with code assist and intelligence in the comfort of your favourite editor.

last push12 days ago languageF# licenseMIT
03 iwe ★ 1.7K

Markdown knowledge graph — LSP for your editor, CLI + MCP memory for your AI agents

last push18 hours ago languageRust licenseApache-2.0

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Frequently asked questions

How many open source language-server projects are there?

This registry tracks 3 projects tagged language-server, with 12,095 GitHub stars between them. The most-adopted is pyrefly at 7,017 stars.

Are these language-server projects free to use?

Yes — 3 of the 3 carry an explicit open-source licence across 2 distinct licences, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.

Which language-server project should I choose?

The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.

Are these language-server projects still maintained?

3 of the 3 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.