If it's just web then it's as crossplatform as vanillajs.
I say this bc I'd be genuinely interested in genuine crossplatform for my client audience of professionals and knowledge workers who, as it stands, are mostly (though not exclusively) Windows users and deserve nice applications.
One difference is that Slint is more mature: it's been 1.x with a stable API since 2023
"Between two operations nothing moves. Instead of sleeping until an animation finishes, the agent says clock +60000 or clock settle and reads the result. No timing flakes, no waits."
From what I see in https://github.com/expo/exact/blob/main/contract/syntax/src/... and https://github.com/expo/exact/blob/main/contract/syntax/src/... - it's unclear this will scale to the levels of complexity that arbitrary UIs demand.
It looks like a DSL, but it actually isn't - it's just regular javascript/typescript with a very thin 'declarative/markup' veneer. it basically tricks you into thinking you're writing a HTML-like UI-DSL, but it also just so happens to accept arbitrary JS expressions, because it is just regular JS.
1 - all logic needs to be written in 1 statement. That forces you to use nested ternaries, nullish operators, and array fns where simple workflow controls would read much better.
2 - it’s designed to render html but conflicts with JS and TS, so you can’t have a class attribute, and weird escape hatches around generic fns.
Because it's a thin wrapper directly translatable into a JS function call. `className` is JS
When I was making a simple vibe-coded app for a hobby group I am part of I finally went ahead with a static hosted web app because everything else quite complex and still used quite a lot of RAM (just for using the f/w).
I think the only better option as of now is – just write native code for each platform. I think the purest cross-platform UI frameowrk is the LLM itself :)
You choose your langage: js, lua, webassembly. You can also make native apps but not documented yet.
It runs on linux, macos, windows, android and the web (ios to come).
- immediate mode 2d - website style 3d - audio, midi, storage, etc - llm ready
This Exact work looks great and I very much hope it succeeds. Qt has Proven this approach works. Now if these folk at Expo can do it at a price that every dev can afford it will get much wider adoption than Qt.
You can't have multi-platform support without external contributors, and of course you can't have external contributors when one dude is pumping out +2.5M LOC in a week.
Like... some way to "branch" out of the main development repo and make changes independent of it before "merging" it back in?
Amazing things are happening in this codebase.
I don’t really get why you would ever want your source code formatted like that, with or without LLMs
It's obvious what its game is
lol
> cross platform - no windows, no android
lol
Yeah I don't think so.
I could vibe code all of this myself if I wanted to. But I don't, because I value my time.
I can just vibe code the actual apps and be fine.
It's a long shot for now, though! There are lot of gritty nitty details they have to get right. One of the first issues I can imagine is this framework being great to use with Opus 5.5 but not good enough with i.e. Gemini 4 Argon or DeepSeek v4.1 Flash 1017, due to the overreliance on having AI models write the code.
The announcement thread covers ways it helps agents, and they sound like things that would help humans, too.
I have been using an internal screenshot feature along with a dump of the component tree. Multi-modal LLMs can be used to read the screenshot and fix issues. The dump can be read by any text based LLM. I made my life much easier.
I saw the Blender UI based framework shared on HN the other day and this one today. I am not sure if I want to continue building my own (although all code is written by agents) or if I should switch. I can take inspiration from the two other frameworks and continue with my own.
Hence me thinking it is satire. Are we already at a point where libraries and frameworks are being written such that they require agents (from maybe paid frontier models) to properly use?
We live in strange times, if so.
Interestingly, I was just thinking of this problem today: how can I stick with react-like declarative UIs (like one I have developed myself) but yet have them abstracted over native UI frameworks of Apple, Android, even TUIs to produce native apps? What I would have expected is a fully deterministic runtime, compiler, or library approach to solving this, not an agent-driven "solution".
Tools like Hyperframes have already demonstrated the value in catering to agentic-first dev while offering manual inspection and editing interfaces.
Agents aren't equally good at all languages/tools, and just having a lot of training data on one ecosystem isn't enough to optimize the experience. If you read the announcement thread from the CEO there are several points made such as formal safeties against invalid states and build error messages that token-efficiently teach the agent correct usage.
> What does "agent native" mean?
https://github.com/expo/exact#1-agent-native defines it
Agent native is said once in this readme, following an immediate explanation and specific features.
It's funny, I'm working on a few different compilers with Claude Code to experiment, and I had an epiphany this morning, we're entering an age in programming, where you could just create your own compiled language (or DSL) for your framework / application effortlessly, it can have whatever requirements you want.
I've also used Claude to help me make Mojo compile under Windows, since they haven't ported it yet, took less than you'd think, downside is the key thing about Mojo is not open source, so I could never port that myself, but at least basic Mojo programs compiled. Might have to try DMD on Apple Silicon next to see...