Yes we developed it ourselves. It's all open source [0] so feel free to fork and modify for yourself.

Inside that repo you'll see two key folders:

    - web: our Docs (built with Docusaurus)
    - www: our website + blog (built with Next.js)

The naming convention could be better.

Both of these are deployed to Vercel as separate "sites" using their mult-zone setup [1]. This setup is so that the docs are deployed on a sub-path (supabase.com/docs), rather than a subdomain (docs.supabase.com)

[0] https://github.com/supabase/supabase

[1] Vercel multi-zones: https://nextjs.org/docs/advanced-features/multi-zones