I just quit what I was w̶o̶r̶k̶i̶n̶g̶ ̶o̶n trying to work on, to go ahead and check on the forum if Webflow is ever going to fix the Designer performance issues (actually I stopped quite a while ago while I read over several posts). I’ve been holding for a few weeks now to post something about this, at least something short to suggest some options, while I was trying to work on some projects, but I cannot wait (or work) any longer. Webflow is just impossible to work with. And now I know for sure it’s not just me or our project.
You guys at WF probably spend most of your day working with code and dev tools, but you probably don’t have to work all day long with an editing tool that doesn’t even allow you to select things without lag, like us. Highly painful, wanting-to-throw-your-computer-out-the-window-every-5-minutes lag and unresponsiveness. A real patience exercise. Why are you torturing us?? What did we do to you?! 
Supposed to bring the designing experience to new highs, WF unfortunately is currently doing the opposite for users.
There’s no way you guys didn’t know since long ago that Webflow is a huge memory hog. That’s the main issue. I don’t know what the cause is. Many pages, classes and interactions have been mentioned. I would also say that the saving process is a big culprit. It doesn’t work in the background as it should, that’s just not true. Instead, it works ON TOP of everything else, and everything freezes when saving is going on, which is like every 10 seconds. You can’t even select things at that moment. Maybe it also has to do with storing the undo history, being why total memory usage keeps growing every minute, as you do more and more actions, until it reaches 2 GB or more, and then you have to close and reopen to gain some time of moderate sanity.
I really thought long ago that this was probably going to be fixed with the big codebase rewrite and React implementation. So I waited patiently and anxiously, but it didn’t. Maybe this was never a priority, until now, which I simply can’t understand. If you have neglected this issue before, it would now be better for everybody to stop what they are doing and have everyone focus on this until you get a performant app.
For reaching that goal, here are some things I would suggest: Look to Vue instead of React (or maybe even Svelte or Imba. Implement GraphQL (via Prisma maybe). Start moving as much as possible to serverless. Use Go as much as possible, too. And go PWA and finally meet the many requests for an offline desktop app in a super elegant, modern way.
Speaking of performant web apps, you should take a look at Figma and how it’s built. That’s how a modern web app should work. This is 2018. We can no longer keep waiting and waiting for months for fixes and small improvements to come live, and keep loosing valuable time every day. I lost hope a while ago, and have started looking for alternatives, like Figma and code converters, and Netlify (which is free btw) and static sites.
I really value your accomplishment in building Webflow as a monumental achievement, and I apologize if this is not the most positive tone, but there’s no way it can be called a professional tool until these issues get fixed (unless “real pros” at big shops and companies really like wasting their time and being slow). It’s either you fix this, or you buy webslow.com.
@iamdustan @callmevlad