Rails is a battle tested choice. Nothing wrong with it. There is no silver bullet that would fit every startup situation. I think the safest "boring" stack is

Rails is a battle tested choice. Nothing wrong with it. There is no silver bullet that would fit every startup situation. I think the safest "boring" stack is PHP with Symfony. It is super easy to deploy, has gotten really good support for gradual typing, very battle tested, good package management and easy to find devs for. Plus you can run your project on a $5 shared hosting and not worry about dev ops and stuff, massively reducing costs. Now, if you know you want to do anything AI, then using Python is also a great option. Also Flask is amazing for making Microservices. The packaging story sucks but there are ways to cope and you will dockerize everything anyway. Or if you are planning on something more challenging which could profit from being on BEAM, why not go the Elixir route? They are still working on the gradual typing features but they are getting there and the functional style helps a lot with managing your state. So yeah, depends what you need. I think golang is excellent for microservices but lacks a good Rails-style framework for cultural reasons. And you shouldn't really go microservice in a startup if you don't have very specific needs. So well, pick your poison. The great thing about backend is that your customers don't care what you use. Might as well deploy Common Lisp if your hearts tells you to.