LoopBack VS express-openapi-validator

Backend is usually an API you design, can simply use Rails for this, basic Express.js or some framework like https://loopback.io/ if you want javascript otherwise you want 'system design' https://github.com/donnemartin/system-design-primer for all the load balancers/dbms if that's what you mean.

LoopBack – Highly Extensible Node.js and TypeScript framework

We deliberately decided not to use "kitchen-sink included" frameworks such as Laravel, Django, Loopback or Nest.js to keep things simple.

Loopback

I'd say check out https://loopback.io

This interface defines the basic CRUD capabilities that any entity should provide. This contract is based on frameworks like Loopback, Django RF, RoR and Spring. The Service.kt looks something like:

The build step is where I put all of them together, which is the messy and tricky part. Although not directly related to your question, I also use this validation tool to handle request validation based on my result yml.

express-openapi-validator Express middleware that routes and validates requests according to an OpenAPI spec.

The express-openapi-validator package addresses this issue by validating requests and responses based on a provided OpenAPI spec. Having our responses validated in addition to just the requests will be a good idea as that will ensure the API code always responds in the expected schema.