# Extend UI

13 Hacker News commenters recommended Extend UI and 10 criticized it, November 2025 to November 2026. It was recommended in 1 of 13 months.

**Verdict:** An open-source React UI kit for building document apps, with a file picker, document viewer and bounding box demos. Reviewers praise the thought behind it but mostly say it needs performance work.

## Why people recommend it

- Saves time, useful for document apps (3 comments): "Great that you took the time to MIT this as it would have saved us many hours" ([source](https://news.ycombinator.com/item?id=48487079)) "this is exactly what we were looking for" ([source](https://news.ycombinator.com/item?id=48482035)) "this could come in super useful" ([source](https://news.ycombinator.com/item?id=48482164))
- Exactly what people need (2 comments): "this is what I need! Hope this project keeps growing" ([source](https://news.ycombinator.com/item?id=48495489)) "this is exactly what we were looking for" ([source](https://news.ycombinator.com/item?id=48482035))

## What people warn about

- Slow, laggy performance (4 comments): "the root page is a bit slow with all the viewers" ([source](https://news.ycombinator.com/item?id=48484138)) "your home page heavily lags on my mbp m3 pro" ([source](https://news.ycombinator.com/item?id=48484807)) "The performance of the "Layout blocks" component is particularly bad. It consumes tons of CPU when scrolling." ([source](https://news.ycombinator.com/item?id=48485411))
- Needs optimization work (3 comments): "Looks clean and works fine, but it needs optimization." ([source](https://news.ycombinator.com/item?id=48484055)) "it'll need some work on optimisation" ([source](https://news.ycombinator.com/item?id=48488352)) "Another AI built project. Which OK, but then at least have a look at it to fix/optimize things." ([source](https://news.ycombinator.com/item?id=48490840))
- Only React supported, Next.js dependency (2 comments): "Leaving out every framework other than React is really bad for the web." ([source](https://news.ycombinator.com/item?id=48480673)) "Next.js as a hard dependency, for a component library, is just weird." ([source](https://news.ycombinator.com/item?id=48488684))
- Rough edges and broken interactions (3 comments): "It has some rough edges as a result, but your suggestions are very valid." ([source](https://news.ycombinator.com/item?id=48489905)) "I can't seem to trigger search functionality and the browser search bar can't find contents on cells" ([source](https://news.ycombinator.com/item?id=48484236)) "Document Splits drag and drop looks weird, like it doesn't drag from where I clicked." ([source](https://news.ycombinator.com/item?id=48493757))

## Alternatives hackers recommend

- [shadcn/ui](https://hackerapproved.com/p/shadcn-ui.md): 82 recommend
- [Jelly UI](https://hackerapproved.com/p/jelly-ui.md): 41 recommend
- [Tailwind UI](https://hackerapproved.com/p/tailwind-ui.md): 38 recommend
- [Performative-UI](https://hackerapproved.com/p/performative-ui.md): 38 recommend
- [Radix UI](https://hackerapproved.com/p/radix.md): 20 recommend

## Cite as

Hacker Approved, "Extend UI", https://hackerapproved.com/p/extend-ui/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).