What is Reddit written in? July 13, 2020 19:12 Updated Python. It was written in Lisp, but we rewrote it (here's why). We use the Pylons framework, and you can see our source code if you want. Related articles What is Embed? What do all these acronyms mean? What happens if the post is edited or deleted after it’s been embedded in an article? Formatting Guide How can I find more communities?