At my company, we decided to slowly move away from our current Rails application to Elixir. At the same time, we don’t have the resources or time to freeze all development for 6 monts and rewrite everything from scratch. That won’t happen.

What we thought is the way to go is that we might start replacing specific routes / components with Elixir applications (going to use Umbrella applications for that).

A large chunk of the Rails application that needs to be ported first is accessible as HTML or JSON/REST. We thought that one possible solution would be to have an Elixir / Phoenix application that would act as a proxy for the requests. If a specific route was already ported to Elixir, it would render the specific route. If not, it would fall back to the Rails application. Also, a quick switch would be nice, so that we can go back and forth in case stuff goes bad during the migration.

Any ideas / suggestions on how to implement that? The closest I could get to this approach is by using Nginx as a proxy, but it’s a bit more complex to allow the switching in a more or less dynamic way.

I’m hoping there is a way to do this in Elixir. Any ideas?