What is the standard web application backend framework for Node.js these days, is it Koa? As I understand it express is quite dated because of the callback structure. I have been confused recently with the moving best practices. What is the server architecture Next.js is most often plugged into?
Express is still fine to use. To me it's either express or fastify. A lot of opinions in the JS world.
Imo the docs need a major re-write, beginning at "getting started". New users don't know whether they should use "fastify-cli gen", "npm init fastify" or copy manually from the "getting started"-guide.
And people also tried to push their fastify-plugins to the top of the plugins-site by adding a "@username" for every plugin: https://i.imgur.com/hHyI6JO.png (left are the old docs, right are the current docs where ppl try to game the system).
Also, fastify-cli needs to rework the custom options in typescript projects imo.
Ok, that's all. Other than that, fastify rocks!