If you were to start buildng a SaaS today, what frontend framework would you use?

I'd avoid using any framework unless I absolutely need to. I'll just stick to SSR as much as possible. For dynamic components, Livewire is just brilliant. So Laravel's TALL Stack all the way. https://tallstack.dev

For CSS I'd use Tailwind.
If it really needs to be SPA, I'd use Mithril JS just because I've been used to it.

But honestly, I'd prefer using old school server-side rendering to reduce the complexity and development time.

I would build backend in laravel and frontend with my own vue.js components library templatium.com

Vue and Tailwind (Nuxt if SSR is needed)

React + My Own Damn Styles™ using CSS Modules. Marketing site in Gatsby.

Angular , Angular Material and Ngrx

Angular. Nothing is more maintainable than an opinionated framework with a statically typed language, and Javascript needs as much maintainability help as it can get.

It always depends from projects requirements, but probably I will go for MERN stack.

React JS with Tailwind CSS

Huh, can't see any jokes about jQuery... Can I be the first one?

Same as I did for my current project: React+MaterialUI+TypeScript
I am very happy with it, not a lot of complaints, development speed was good and results were awesome.

I like your choices and of the popular JS front-ends, Vue is probably my favorite.

I'd probably use Phoenix LiveView so I don't need to mess with a JS framework at all, and use Tailwind for the styling.

Flask baby! Simple and to the point.

I'm prefer React so I highly recommend Ant Design. Comes with tons of awesome SaaS dashboard components out of the box completely free and open source. Helps me get going quickly.

Vue and Tailwind 4 lyf... and a bit of blade, since I use Laravel :)

VueJS,Nuxtjs,tailwindcss .

VueJS + Vue Router + Vuex + Tailwind CSS + Tailwind UI

React with CRA using the typescript template, CSS with tailwind (of course!), and apollo-client and graphql codegen for talking to the backend API and getting some really nice types for all data models.

React with CRA or Nextjs, most likely bootstrap until tailwind have a reactjs library

I used Vue & Tailwind to build Nodewood because it was super simple and quick for me, and is going to be super-simple and quick for anyone else who uses Nodewood.