Coi
Languages and libraries
compiled ui language
SHOW HN2026
225points
69comments
#234of 4,366 in 2026
Top 6%of 2026 by points
How HN took it
CuriousMostly questions and neutral comments
10 positive, 21 neutral or asking, 0 mixed, 6 critical, out of 37 comments about the project. Thread score +0.11.
Design: 1 for, 4 againstExecution: 3 for, 1 againstIdea: 4 for, 0 againstPerformance: 0 for, 1 against
The thread, comment by comment
Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.
positive neutral or mixed critical about another commenter or something else the maker
What HN said
What people liked
Shared-memory command buffer design is clever
From 2 comments
Gotta say the Shared Memory approach is genius. Finally someone's cutting down the clunky back-and-forth.
frankhsu on HNI love the idea and execution. I did some reading of the code webcc and it's just brilliantly simple, and delivers to the promise. From the product perspective, it occupies a…
trzeci on HN
Compile-time reactivity without virtual DOM
From 2 comments
> It’s a component-based language that statically analyzes changes at compile-time to enable O(1) reactivity. Unlike traditional frameworks, there is no Virtual DOM overhead This…
kccqzy on HNI think this genuinely might be the first time I'm seeing a language rework for UI's that actually makes sense and incorporates all that we've learned in the modern age about UI…
written-beyond on HN
Small binary size and fast builds
From 2 comments
Pretty fast. It doesn't drag in the C++ standard library, so builds stay lean. My demo page takes about ~1s to compile for me (after the first time)
io_eric on HNBinary size alone got me interested. What's missing before 1.0?
hans2002 on HN
Objections
Benchmark claims seemed suspicious versus Emscripten
From 1 comment
First: very nice project, kudos! But: > It’s way more efficient, I ran a benchmark rendering 10k rectangles on a canvas and the difference was huge: Emscripten hit around 40 FPS,…
flohofwoe on HN
HTML-like syntax with control tags feels unnatural to JS developers
From 2 comments
I don't like this html-syntax, cause you use a separate syntax-methods for existing js-functions wrapped as html-tags: ``` <if text.isEmpty()> <div class="preview-text…
progx on HNsounds cool, want to explore this a bit, however, why XML if condition? > <if score >= 10> this looks kinda cursed, makes me wonder how it's even parsed
gloosx on HN
Adds yet another language with no clear need for new syntax
From 2 comments
What are the exact features that require it to be a new language with new syntax?
LudwigNagasena on HNSounds interesting! But do you think it would be possible to achieve similar results without a new language, but with a declarative API in one of your existing languages (say,…
rthrfrd on HN
Requests
Interop with npm/JS libraries
From 2 comments
I think this genuinely might be the first time I'm seeing a language rework for UI's that actually makes sense and incorporates all that we've learned in the modern age about UI…
written-beyond on HNSounds really cool. A few things I think should be considered: 1. Global state management? Props drilling really sucks... 2. How to deal with network? API is a must... 3.…
syabro on HN
Global state management and networking support
From 1 comment
Sounds really cool. A few things I think should be considered: 1. Global state management? Props drilling really sucks... 2. How to deal with network? API is a must... 3.…
syabro on HN
DWARF debug builds and compile flag control
From 1 comment
I love the idea and execution. I did some reading of the code webcc and it's just brilliantly simple, and delivers to the promise. From the product perspective, it occupies a…
trzeci on HN
Questions
How does it compare to Svelte performance?
From 2 comments
Did you compare with Svelte?
orphea on HNCame to ask this. React and Vue aren't exactly known for their performance and Svelte does compile time optimizations.
k__ on HN
How to integrate into existing JS framework projects?
From 1 comment
This looks very interesting! Do you have any tips/pointers on how one could use Coi to generate a component and then integrate it into an existing project which uses a…
iamsaitam on HN
What is missing before 1.0?
From 1 comment
Binary size alone got me interested. What's missing before 1.0?
hans2002 on HN
Alternatives named
Emscripten
From 2 comments
> It’s way more efficient, I ran a benchmark rendering 10k rectangles on a canvas and the difference was huge: Emscripten hit around 40 FPS, while my setup hit 100 FPS. Just…
publicdebates on HNI love the idea and execution. I did some reading of the code webcc and it's just brilliantly simple, and delivers to the promise. From the product perspective, it occupies a…
trzeci on HN
React
From 1 comment
Came to ask this. React and Vue aren't exactly known for their performance and Svelte does compile time optimizations.
k__ on HN
Svelte
From 2 comments
Did you compare with Svelte?
orphea on HNSvelte used to have compile-time reactivity, but switched to runtime reactivity via signals: https://svelte.dev/blog/runes I'm curious if Coi will also suffer from the drawbacks…
Leftium on HN
Leptos
From 1 comment
Nice work ! Thanks for shating It reminds me of https://leptos.dev/ in Rust, although the implementation might be very different
merqurio on HN