While ITA no longer exists as a separate entity I don’t think, my understanding is that they pretty much wrote everything in Lisp. https://en.wikipedia.org/wik

While ITA no longer exists as a separate entity I don’t think, my understanding is that they pretty much wrote everything in Lisp. https://en.wikipedia.org/wiki/ITA_Software https://en.wikipedia.org/wiki/ITA_Software https://franz.com/success/customer_apps/data_mining/itastory.lhtml https://franz.com/success/customer_apps/data_mining/itastory... Grammarly too, although I don’t think it qualifies as a 20-year codebase: https://www.grammarly.com/blog/engineering/running-lisp-in-production/ https://www.grammarly.com/blog/engineering/running-lisp-in-p...