Callbacks in JS aren't really dated, just many of the patterns associated with them are. The Promise constructor itself takes two callbacks as its arguments. A

Callbacks in JS aren't really dated, just many of the patterns associated with them are. The Promise constructor itself takes two callbacks as its arguments. Async/await are just syntax sugar over that constructor. Express supports promise-based mw callbacks just fine. So I'd still say Express is the main choice. Personally I've never loved the Express API as it encourages a lot of heavy mutation (Koa does too), so I tend to be on the lookout for good alternatives - I haven't seen any that seem to be sticking (gaining significant enough community to bet on) more than Express. There's a few things like Next/SvelteKit that cover all bases in one, from your web app backend -> SSR frontend -> client states, but if you're looking at pure backend for e.g. an API, Express is still going strong.