The company that google bought for flights (ITA?) was built on SBCL and flights is still written in it. Pretty huge codebase from what I heard

If I remember correctly, Google even contributes to SBCL because of that.

Grammarly used SBCL in production:

https://www.grammarly.com/blog/engineering/running-lisp-in-p...

It also sounds like they were very much a polyglot shop.

The first version of Reddit was written in Common Lisp, but less than a year later, they reluctantly migrated to Python because Python had a bigger library ecosystem:

https://web.archive.org/web/20160803061607/http://www.reddit...

I remember a more nuanced version:

- They tried using some commercial Lisp on a platform where it was poorly supported, and were struggling with certain stability issues (I don't remember the details).

- A team member came on board who, what do you know, had also authored the Python-based web framework that they were using in the rewrite. Reddit may have been used as the "guinea pig" for improving this web framework.

Sorry, I misremembered all that. It's hard to find the original information. One of the devs revealed that he was working OpenMCL on a Mac ... but then Reddit was actually running with CMUCL on FreeBSD. (Yes, really!) He couldn't basically even run all of Reddit in the dev environment.

(Regarding "commerical Lisp"; that's what some Lisp people were saying should have been given consideration.)

Some quantum computing companies use SBCL, specifically to build optimizing compilers [1], quantum computer control systems, and quantum simulators.

[1] https://chromotopy.org/latex/papers/quilc.pdf

Here's a recent one, which leads to a couple more: https://lisp-journey.gitlab.io/blog/lisp-interview-kina/ and to a (non official and growing) list of companies using CL: https://github.com/azzamsa/awesome-lisp-companies/

Not SBCL, but HN is written in Arc (a Lisp).

Circle CI is apparently written in Clojure.

Kandria, Open world RPG: https://reader.tymoon.eu/article/413

Discussed here:

Technical overview of Kandria, a game and game engine developed in Common Lisp - https://news.ycombinator.com/item?id=32043026 - July 2022 (32 comments)

lisp startups are usually too busy doing unconventional things to advertise what they use. dunno why, just stating an observation