Extend UI
MIT-licensed React component kit for document-heavy apps — PDF/DOCX/XLSX viewers, bounding-box citations, uploads, e-signatures, layout blocks, and Finder-style file browsing. Installed via shadcn registry (
@extend/*).
Built by Extend (document intelligence API). Open-sourced after internal use processing millions of pages. Launch tweet: 2,515 bookmarks. Source: X/@kushalbyatnal, 2026-06-09
What it includes
14 components + examples, copied as source into your repo (shadcn model): Source: GitHub extend-hq/ui, https://github.com/extend-hq/ui, 2026-06-12
| Component | Capabilities |
|---|---|
| PDF viewer | Page controls, zoom, search, text selection, thumbnails, uploads, responsive layouts |
| Bounding box citations | Highlight regions tied to extracted text — critical for document agents |
| XLSX viewer | Sheet tabs, frozen panes, formulas, large-grid navigation, cell selection |
| DOCX editor | Word-style toolbar, import/export, formatting, thumbnails, links, images, tables, tracked changes |
| E-signature | Place, review, complete signature fields on PDFs |
| Layout blocks | OCR/layout output with selectable blocks, confidence, markdown text, PDF overlays |
| File upload / thumbnails / file system | Agent-facing document workflows |
Docs: https://ui.extend.ai/ · GitHub: https://github.com/extend-hq/ui (931+ stars at launch). Source: ui.extend.ai, 2026-06-12
Version Snapshot
Checked 2026-08-12:
- GitHub repo:
extend-hq/ui - Default branch:
main - Default branch HEAD:
1d9e8c0edd5c77aa363b6b76cae828206cf5ff95 - GitHub status: TypeScript, 1,375 stars, 67 forks
- GitHub license field:
NOASSERTION; resolve the exact copied component and repository license text before redistribution - Detected source surface: no test files or CI workflows in the captured tree; prove document fidelity, keyboard/screen-reader behavior, large-file performance, citation coordinates, and editable-source integration locally
Source: commit-pinned repository receipt, 2026-08-12
Install
npx shadcn@latest add @extend/pdf-viewer
Components expect your app's existing shadcn primitives (Button, Dialog, ScrollArea, etc.) — update import aliases in generated files or components.json before install. Source: GitHub extend-hq/ui, 2026-06-12
import { PDFViewer } from "@/components/ui/pdf-viewer"
export default function Page() {
return <PDFViewer file="/sample.pdf" className="h-[720px]" />
}
Why it exists
Extend evaluated existing file viewer libraries and needed more complete, polished blocks for document agents and user-facing review surfaces. Components are maintained in production at Extend and fed back into the OSS repo. Source: GitHub extend-hq/ui README, 2026-06-12
Stack fit
- Document agents — viewer + citation UI pairs with Vercel AI SDK / Plate (PlateJS) backends.
- Registry pattern —
@extend/*namespace aligns with Shadcn Registry Directory (Top Blocks) custom registries. - Design-system agents — source-installed components are editable by Cursor/Codex for prototyping.
Built by @andrewlu0 per launch thread credit. Source: X/@kushalbyatnal thread, 2026-06-09
Timeline
- 2026-08-12 | Refreshed the source to commit
1d9e8c0, 1,375 stars, and 67 forks; recorded GitHub licenseNOASSERTIONand missing detected tests/CI as adoption gates rather than inferring production readiness from the demo. Source: commit-pinned repository receipt - 2026-06-09 | @kushalbyatnal launch: Extend UI open-sourced, 14 components, MIT, shadcn registry. Thread demos PDF/Excel/DOCX/e-sign. 2,515 bookmarks. Source: X/@kushalbyatnal, 2026-06-09
- 2026-06-30 | Refreshed repo snapshot: default branch HEAD
626117b8a43b98d935370f71f4762fc06de6c3fa, 1,218 stars, 61 forks. Source: GitHub API;git ls-remote, 2026-06-30 - 2026-06-12 | Wiki page from bookmark absorption (thread + GitHub + site). Source: User, 2026-06-12