Comment by yoavm

I always thought Accept (and Accept-Language) headers are quite neat. Surely I can try article.es.md first, get a 404, try article.en.md, get a 404, try article.es.txt, article.en.html and so on, until I find the thing I'm looking for. But Accept let's me say "I'll take any one of these, preferably in this order". This is especially useful now when agents are reading the web and they don't really need all of our HTML code - just the text.

If you're versioning the whole API though, I agree it's best behind a a /v2/ prefix.