What programming language is duolingo.com written in?

Question

Programming

I decided to ask if anyone knows what this site ( www.duolingo.com ) is written on? Or how can you find out. Painfully interesting everything is done there. Thanks in advance.

Answer 1

In Python. I, usually, if I can’t immediately determine the language, I look at vacancies in the company. They have a Software Engineer job that says "Strong coding skills in Python, JavaScript/AJAX, database design and SQL". It is very likely that python is used, since it is specified in the context with JavaScript and the database.
Upd: Also, I found a comment from Brendan Meeder who works there:

Duolingo runs on Amazon Web Services. We use MySQL to store most of our persistent data, DynamoDB for storing user vocabularies, and a combination of Redis and memcache for caches. Most of our backend stack is written in Python, while the frontend is a combination of mustache templates, backbone.js, jQuery, and Twitter Bootstrap.

Answer 2

The server is Ruby, but there is little interesting there. All the fun is on the client side (javascript).
You can find out by the headings like X-Runtime or X-Powerd-By. Unfortunately, the latter is hidden on this site, but X-Runtime seems to be similar to the one that spits out RoR.