Welcome to Common-Lisp.net

Welcome to the amazing world of Common Lisp, the programmable programming language.

A live REPL, shared: type into itC-l clears the screen · C-d restarts the Lisp Open in a full console ↗

This site is one among many gateways to Common Lisp. Its goal is to provide the Common Lisp community with development resources and to work as a starting point for new programmers.

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What is Common Lisp?

Common Lisp is a modern, multi-paradigm, high-performance, compiled, ANSI-standardized descendant of the long-running family of Lisp programming languages.

Common Lisp is known for being extremely flexible, having excellent support for object oriented programming, and fast prototyping capabilities. It also sports an extremely powerful macro system that allows you to tailor the language to your application, and a flexible run-time environment that allows modification and debugging of running applications (excellent for server-side development and long-running critical software). It is a multi-paradigm programming language that allows you to choose the approach and paradigm according to your application domain.

Curious?Get started!More about the language

Services

Project hosting for open source Common Lisp: a Git repository on gitlab.common-lisp.net with CI on every major implementation, a web page at <project>.common-lisp.dev and a mailing list.
Mailing lists for Lisp topics that are not a project.
Container images of the Lisp implementations, and custom images built to order.

All the services

Support

Stuck with something on this site or on its GitLab? Ask in #common-lisp.net on Libera.Chat, or send the admins a request.

About this site

Run by volunteers, held by a non-profit, and paid for by its services and by gifts. The pages are a Common Lisp program, and its source takes merge requests like any project here. More on the about page.

Latest Common-Lisp.net news

5 October 2026
A live REPL on the front page
The session on the front page is now a real Common Lisp, running in a container on our own server, and everyone on the page shares it: what you type, the others see, and what someone defines, you can call. It starts each time by typing in the hello-world that used to be written there. "Open in a full console" next to it opens Emacs and SLIME, connected to the same Lisp, for longer work.
3 October 2026
Weekend skin, Libraries page
The Weekend "Hacker" skin is now off unless you ask for it. The Libraries page no longer lists individual libraries; its list had been a stale copy of Awesome Common Lisp. The page now links to Quicklisp, Ultralisp, Awesome Common Lisp, CLiki and a few others, sorted by when each was last updated, which the site looks up by itself. The old list is still at old.common-lisp.net.
3 October 2026
A meeting room, with recording
As you may know, common-lisp.net hosts a video conference room that is always open: the commons. It is Jitsi Meet running on our own server, it needs no account and nothing installed, and it is there for anyone who wants to talk about Common Lisp. The room now offers a recording service. Recordings draw on the community pot (next item). Additional Jitsi rooms can be made by registered administrators by asking the admins to become a Jitsi admin.

Latest Lisp news

From Planet Lisp, which collects the Lisp blogs.

Active projects

mantoniotti/threadmilambda
A revamped threading and concurrency library based on Bordeaux Threads. Done in MILan.
gendl/gendl
Generative Programming and KBE system embedded in Common Lisp --- #gendl on libera.chat
clo/cl-site
cmucl/cmucl
CMUCL is a high-performance, free Common Lisp implementation which runs on most major Unix platforms.
clm/meeting-kit
clo/meet-kit

961 public projects on gitlab.common-lisp.net. Explore them