I’ve spent a fair amount of my professional life building and/or maintaining one-person apps in production (or two-to-four-person apps, which is not as catchy of a name but has many similarities). I don’t think you should focus too much on the idea of a literal single person, but rather, on the ability to maintain an application with a very modest input of developer resources. IMO both Rails and Phoenix are both best in class in this category.
What DHH mentions in passing is that there was a golden era in which Rails really did make it possible for a single person with mid-level experience to maintain a complex web application and even enjoy doing so! The rapidly escalating demands and complexity of the frontend have dashed that possibility for many web applications. These days, rich UI experiences are a baseline expectation for many apps, and rich UI experiences are very hard to build without committing to a heavy frontend framework, which these days is typically React. Not only is React a different language, it’s a completely different paradigm with almost entirely novel conceptual models, performance concerns, development tooling, etc. It’s a lot for even a very senior dev to keep a handle on while simultaneously maintaining a backend. To make matters worse, the huge amount of churn in Javascript packages means you are perpetually on the hook for breaking updates, abandoned modules, etc. Adding React to a non-toy project introduces a huge maintenance liability and puts you on a swift track out of one-person-app land.
To me, one of the biggest value propositions of LiveView is that it greatly expands the scope of which projects can avoid introducing React and incurring all this liability. LiveView makes it possible to build UIs that are rich and performant enough to satisfy the needs of many modern web apps, and it is powerful enough to remain in one-person-framework land while doing that. A lot of Rails apps have React dependencies even though they’re not doing anything especially fancy, simply because Rails hasn’t historically had a good answer for what to do when you need more than “a sprinkle” of JS but less than the whole enchilada. I haven’t used Rails 7 yet but it will be interesting to see if it makes headway in this area.
To answer the original question about when I would choose one versus the other, here’s how I would look at it in the current moment:
- If my app needs very little rich UI, I can write a little bit of vanilla JS, skip React, and use Rails or Phoenix. Either one is good.
- If my app needs a lot of rich UI, I can suck it up and use React, and the backend can be Rails or Phoenix. Either one is good.
- If my app needs some rich UI, I can use Phoenix+LiveView and skip React. Phoenix is the clear winner at the moment.
