We have a an aging rails monolith that gets cast aside whenever there's more important work to do, which is most of the last 8 years or so. The maintainer (my old boss) stopped deploying properly and there was code drift on prod.

He left, my time freed up because claude, and I gave claude the directive of making an API to use with a Vite frontend so we can rebuild the UX carefully with user input along the way, and the end result will be running the monolith in parallel while users migrate to the new platform, monitoring, then phasing out the rails app. I'm skipping over a lot of the details, but so far so good, there's a light at the end of the tunnel.

If I was rebuilding the same app today, I'd still probably use rails as the API layer. The conventions are great, it's readable for when you need to read it... before AI the JS community was forever hunting for the "rails for node" and never got it. I think that says something.