Remix.run Logo
Show HN: Extend UI – open-source UI kit for modern document apps(extend.ai)
146 points by kbyatnal 9 hours ago | 36 comments

We're open-sourcing 14 components & examples today for PDF, DOCX, and XLSX viewers, plus bounding box citations, file upload, e-signature, and more. It's MIT licensed and fully customizable.

Demo video here: https://share.extend.ai/kRmSGKRF

When we started, we tried every file viewer and document component library we could find. Unfortunately, none of them had all the functionality (and polish) that we wanted, so we ended up building our own for https://extend.ai/. It was only ever meant to be internal, but enough customers kept asking for it that we decided to open source it.

It's useful for building document processing agents, real-time user facing document intake flows, or all kinds of internal tooling.

We naively thought this would be a solved problem. Turns out, making PDF/XLSX/DOCX viewers that work at scale is not trivial...we use and maintain it for Extend ourselves, so we've fixed a lot of edge cases that came up while running millions of pages / day through our own system. Our hope is that with our resources + community support, it'll keep getting better over time.

dvt 5 hours ago | parent | next [-]

Super cool. Working on a local AI tool specifically for document workflow automation (where context = screen/web/folders/files), and this could come in super useful. I do most of the PDF/DOCX/etc. parsing natively in Rust, but having a nice way to see the output without spinning up Word or Powerpoint is a huge leap.

Thanks for releasing publicly.

andrewlu0 5 hours ago | parent [-]

nice - did you write a custom parser for PDF/DOCX? we wrote one for XLSX after running into event loop issues with sheet JS

dvt 5 hours ago | parent [-]

Using lopdf[1] for PDF parsing, rtf-parser[2] for RTF, calamine[3] for XLSX, and I'm sure you know that DOCX/PPTX/etc. is basically just a zip file of XML + text. The LLM cares about textual data (which just gets moderately cleaned up post-extraction), so I (thankfully) didn't have to deal with rendering. But showing a preview or end-result to a user would be a huge plus, so I can see myself using your library.

[1] https://github.com/J-F-Liu/lopdf

[2] https://github.com/d0rianb/rtf-parser

[3] https://github.com/tafia/calamine

petilon 3 hours ago | parent [-]

What about rendering? That's the hard part.

andrewlu0 2 hours ago | parent | next [-]

we built a library @extend-ai/react-xlsx on top of it that renders the parsed contents onto a canvas

testing was mostly manual with a test corpus we generated. its not perfect but its pretty close for most files we've seen

dvt 3 hours ago | parent | prev [-]

For me, rendering was just a nice-to-have.

petilon 3 hours ago | parent [-]

Sorry I meant to ask the author of Extend UI not you.

CraigJPerry 6 hours ago | parent | prev | next [-]

Those bounding box demos are decent.

By quirk of fate i've spent the past 2 days prototyping some stuff on pdfjs. Just trying to figure out a game plan for handling bounding boxes in the face of page zooming, different resolutions etc. etc. I can't see it mentioned whether the components are virtualising pages (as in reusing dom elements as document pages scroll by). I guess i just learned what i'll be exploring tomorrow then...

andrewlu0 6 hours ago | parent [-]

yes - the pdf/docx viewer use react-virtual to virtualize the pages

the zoom should work with the bounding box highlights, we're working on adding rotation support

promiseofbeans 31 minutes ago | parent | prev | next [-]

How is your PDF coverage? They are notoriously difficult things to render, with endless edge cases. Mozilla’s PSD.js is the status quo here, so what do you do better than them?

andrewlu0 21 minutes ago | parent [-]

We use react-pdf for the viewer which I believe uses pdf JS under the hood

We aren’t not trying to reinvent that engine, rather just provide a building block for people to plug in their design system to its controls

pea 38 minutes ago | parent | prev | next [-]

Looks cool but your home page heavily lags on my mbp m3 pro - you should maybe be lazy loading vs loading all your components upfront

andrewlu0 19 minutes ago | parent [-]

Valid feedback a few other comments have mentioned , I’m going to try improving the home page tomorrow

egeozcan 5 hours ago | parent | prev | next [-]

Why doesn't it mention anywhere that they are React components?

andrewlu0 5 hours ago | parent [-]

we'll try to make it more clear on the landing/introduction page!

hju22_-3 2 hours ago | parent [-]

_Try_ to? Are you serious? We're not taking ambiguity due to phrasing, we're talking straight up not mentioning it on either the front page, on the show all page or even on the page the components button takes you to. Not even on this forum thread. There's barely any text on the front page to change and there are even multiple places you can mention React. You could mention it in the title, e.g. "Open source _React_ UI kit for modern document apps" or you could add it to the second paragraph, e.g. "React components ready to drop into user-facing flows, agents, or internal tools." Not to mention the components page. And given what you use to make the website, how does it take this long to update something this trivial when you are going out of your way to promote it, replying to comments and your other services by proxy?

Also, add either user interactive loading of components or lazy load the demos, the amount of demos murder performance on phones.

andrewlu0 2 hours ago | parent | next [-]

coming back to this now and added it in a few places

on the demos - everything below the fold is lazy loaded but i will see what we can do to improve the mobile perf

digitaltrees an hour ago | parent | prev [-]

Tone.

qreoct 2 hours ago | parent | prev | next [-]

Cool project! I was playing around with the Excel viewer - the docs claim "Search across sheets and cell ranges", but I can't seem to trigger search functionality and the browser search bar can't find contents on cells.

Is this a known issue?

phonon 2 hours ago | parent | prev | next [-]

How does it compare to https://news.ycombinator.com/item?id=48436863 ?

andrewlu0 2 hours ago | parent [-]

if you mean our docx viewer/editor specifically its hard to say without manually testing the visual fidelity with Word on some complex docx files

you are welcome to try it with your own documents and see, but its just one example we wanted to show. for the blocks that use the react-docx library, you can always copy the code and use a different method to render the docx file/thumbnails

spankalee 7 hours ago | parent | prev | next [-]

These should really be web components. Leaving out every framework other than React is really bad for the web.

digitaltrees 43 minutes ago | parent | next [-]

Then build it yourself. They do work for free, give it to the world, and your response is: do it differently the way I want.

andrewlu0 5 hours ago | parent | prev [-]

thats fair and definitely something we can try supporting in the future. we started with React because of how familiar models are with shadcn and tailwind

we hope this can be useful for people building in React though!

hobofan 5 hours ago | parent | prev | next [-]

Thanks, that looks awesome! We were looking to add DOCX and XLSX preview to our app, and were planning to do server-side conversion to PDF (which seems to be what most other apps resort to) due to the lack of good libraries to render it, and this is exactly what we were looking for! :)

andrewlu0 5 hours ago | parent [-]

thanks! would love to get your feedback

i can't promise its visually 1:1 with Word/Excel but its pretty close on the corpus we tested with

plastic041 2 hours ago | parent | prev | next [-]

Looks clean and works fine, but it needs optimization. Clicking "Type" in the "schema builder" example takes 1~2 seconds to open the popover in the landing page(macbook pro m4). I think its because there are lots of heavy components, but still it's too slow.

andrewlu0 2 hours ago | parent [-]

it should be much faster on the individual component's page

the root page is a bit slow with all the viewers, in practice you probably wont have that many in your app on one page

warthog 7 hours ago | parent | prev | next [-]

really like these - curious how the xlsx editor and viewer is built in that what kind of headless spreadsheet?

could not have been easy

andrewlu0 6 hours ago | parent [-]

Hi! I'm one of the engineers at Extend that worked on this - one of our other engineers created a Rust XLSX/XLS parser that we ported to WASM to our @extend-ai/react-xlsx package which handles the rendering/charts. It exposes some hooks so users can use their own components for the toolbar

drivingmenuts 6 hours ago | parent [-]

How much was actual engineering and how much was telling an AI what to do?

dvt 3 hours ago | parent [-]

Even if it was just prompting, not sure how that takes away from the final, fairly polished, product. How do you define "actual engineering"?

stinger 3 hours ago | parent | prev | next [-]

Does it/will it support Markdown files?

andrewlu0 2 hours ago | parent [-]

i felt like we couldn't build much on top of react-markdown, which i think is what most people are using

KolmogorovComp 6 hours ago | parent | prev [-]

> This page could not load

On mobile Safari…

andrewlu0 5 hours ago | parent [-]

hm seems to look ok on mine - is this on the root page?