It depends on what you mean by production! I am using Supabase in a hobby-level project that's "in production" (aka live on the internet). Supabase uses Deno to deploy functions. I am currently using Supabase functions (which are Deno Deploy functions) for both an API (interfacing with data not in a Supabase database) as well as some web-hook listener fuctions that keep Supabase accounts in sync with Stripe user IDs.

Overall, no issues or complaints. It's always a bit odd coming from npm/node into something like Deno, but the differences are really trivial. I believe Deno has become much more compatible with Node since I really had to update the project, so the differences are probably even smaller now.